The Cytology of Sheep Rumen Ciliates. I. Ultrastructure of Epidinium caudatum Crawley1

Epidinium caudatum has an anterior vestibulum containing the adoral zone syncilia (AZS) on an extrusible peristome. The cytopharyngeal structures include a funnel-shaped arrangement of nematodesmata, longitudinal and transversely oriented microtubular ribbons all of which are located in the peristome, a structure which also contains filamentous phagoplasm. The origins of the microtubular ribbons indicate affinities to the rhabdos type of cytopharynx. The peristomal base is continuous with the tubular esophagus, the region connecting the two being ensheathed by a fibrous layer and low density cytoplasm. The esophagus has a microtubular/microfilamentous wall. A distinct cytoproct with associated myonemal structures occurs posteriorly. The skeletal plates consist of a large number of interconnected, variably shaped platelets and may have dual skeletal and storage functions. The endoplasm is more vesicular than the ectoplasm, the two separated by a fibrous boundary layer. The five-layered cortex has an external glycocalyx, a plasma membrane with two subtending membranes, homogeneous, microtubular, and microfilamentous layers. The syncilia of the AZS are mounted in a U-shaped band on the peristome with transversely oriented kinetics consisting of kinetosomes linked by a sub-kinetosomal rod. There is a bifurcated kinetodesma, dense support material forming a lateral spur with associated transverse microtubules, and postciliary, interkinetal, and occasional basal microtubules, nematodesmata, and a subciliary reticulum. A barren, possibly vestigial, somatic infraciliature consists of non-ciliated kinetosomes and a basal striated fiber with associated basal and perpendicular (cortical) microtubules.     

The Cytology of Sheep Rumen Ciliates. II. Ultrastructure of Eudiplodinium maggii1

The anterior adoral zone of syncilia (AZS) of Eudiplodinium maggii is mounted on an extrusible peristome within a vestibulum. The peristome contains cytopharyngeal components derived from the infraciliature. These components include a crescent-shaped palisade of nematodesmata, two types of sub-membrane cytopharyngeal ribbons, and an ensheathing fibrous layer enclosing a phagoplasmic zone containing the other components. A convoluted esophagus is continuous with and extends from the posterior of the cytopharynx adjacent to the macronucleus. A posterior cytoproct has specialized cytoplasm around it and associated myoneme-like elements. The skeletal plate is composed of finely granular platelets and lies under the cortex ventral to the macronucleus. The endoplasm is separated from the ectoplasm by a fibrous boundary layer. The cortex has an external glycocalyx, a membranous layer, epiplasm, and microtubular and microfilament layers. The AZS infraciliature is of the usual cntodiniomorph type, kinetosomes linked by a sub-kinetosomal rod and with associated bifurcated kinetodesma, postciliary and transverse microtubules-the latter extending into the cytopharynx—nematodesmata, and a fibrous reticulum. A possible vestigial, somatic infraciliature consisting of short, barren kinetosomes with associated basal and cortex-directed microtubules and a periodic incomplete fiber, is found subcortically throughout the cell.     

The Functional and Evolutionary Significance of the Ultrastructure of the Ophryoscolecidae (Order Entodiniomorphida)1

ABSTRACT. Ophryoscolecid ciliates from the order Entodiniomorphida show a series of morphological types which have been interpreted as an evolutionary lineage. In this study, ultrastructural information from three species—the ancestral Entodinium, intermediate Eudiplodinium maggii, and the advanced Epidinium—has been evaluated in terms of ophryoscolecid evolution. The infraciliature, nuclei, contractile vacuoles, cortex, and cytoplasm are all very similar and sometimes indistinguishable among the three species, suggesting a close relationship. The cytoalimentary system, however, shows considerable interspecific variation. The cytopharynx differs in position and extent of microtubules and microfilaments, varying in appearance from a microtubular to a microfilament-based mechanism while retaining similar component structures. The esophagus, a zone of cytoplasm extending from the cytopharynx and delimited by a microtubular/fibrillar wall, is rudimentary in Entodinium, sac-like in Eudiplodinium, and tube-like in Epidinium, where it also has convoluted walls and a sheath of fibrous material that suggest an expansible-contractile structure. These variations have been related to type of food particle ingested. The capability of the cytoalimentary systems seems to be increased so that the more advanced forms can exploit a food resource, in the form of large plant fragments in the ruminal fluid, not available to the simpler, ancestral forms, which tend to ingest small particles such as bacteria and starch grains. The original evolutionary lineage based on morphological studies using light microscopy is supported by our observations, in these three forms, of ultrastructural variations in the cytopharynx and in their relationship with diet via possible ingestion mechanisms. Additional support for this evolutionary analysis comes from preliminary studies of other ophryoscolecids in which the cytoalimentary organization is consistent with their positions relative to one another in the evolutionary scheme.     

Morphogenesis and Cortical Ultrastructure of Brooklynella hostilis,a Dysteriid Ciliate Ectoparasitic on Marine Fishes*

SYNOPSIS. Morphogenesis, and the cortical structures of Brooklynella hostilis, a cyrtophorine gymnostome ciliate ectoparasitic on marine fishes, were studied from protargol silver-impregnated preparations and with the aid of electron microscopy. The pattern of morphogenesis of Brooklynella is close to that found in less differentiated species of the families Chlamydodontidae (e.g., in the genus Trithigmostoma) and Dysteriidae (e.g., in the genus Hartmanula). The full number of kineties in the opisthe is restored after division from a segment of the left one of the 3 kinetics producing the oral rows. The oral rows consist of a double row of kinetosomes arranged in a zig-zag pattern; only the outer row is ciliated, the inner one being barren. However, the positions of the postciliary and transverse fibers indicate that the oral rows are not homologs of an undulating membrane but are akin to a membranelle. In association with the ventral somatic kinetosomes there are 4 postciliary fibers; a rather aberrant, transversally oriented kinetodesma; 2 microtubular, transverse fibers plus a transverse fibrousspur; and one to several ribbons of subkinetal microtubular fibers. Not directly associated with the kinetosomes are fibrous strands running subpellicularly between the kinetosomes and also deep into the cytoplasm. The cortical structures of Brooklynella are compared with those of some other groups of ciliates of about the same phylogenetic level in which the subkinetal microtubules can also be found– rhynchodine, suctorian, and chonotrich ciliates. The nasse consists of 6–8 nematodesmata not closely associated with the microtubular cytopharyngeal tube. The former have a distinctly developed densely fibrous capitulum containing barren kinetosomes which originally produced the nematodesma during stomatogenesis; the capitulum is connected by a fibrous link to the microtubular shaft. Extending from the oral rows to the capitula are fibrous structures strongly reminiscent of filamentous reticulum in hymenostome and peritrich ciliates. The structure of the posterio-ventral glandular organelle is also described and discussed.     

Oral Monokinetids in the Free-Living Haptorid Ciliate Enchelydium polynucleatum (Ciliophora,Enchelyidae): Ultrastructural Evidence and Phylogenetic Implications1

Special ultrastructural characteristics of the haptorid soil ciliate Enchelydium polynucleatum Foissner, 1984 are the restriction of the parasomal sacs to the area of the “brush” and finger-like projections of the food vacuole membrane into the lumen of the vacuole. The general organization of the infraciliature is similar to that of Spathidium and some buetschliids because the anterior ends of the somatic kineties are condensed and obliquely bent. Enchelydium is similar to haptorids and buetschliids in possessing monokinetid somatic fibrillar structures with the classical fibrillar associates: 1) a short kinetodesmal fiber; 2) two transverse microtubular ribbons; 3) a long postciliary microtubular ribbon; and 4) a system of overlapping subkinetal microtubules, which seems to be absent in the buetschliids. Unlike Spathidium and all other haptorids so far investigated ultrastructurally, serial sections show that there are no oral dikinetids, as in the endocommensal buetschliids and balantidiids. Instead, three to six anterior kinetids in each ciliary row have nematodesmal bundles extending into the cytoplasm and surrounding the cytopharynx. These kinetids lack cilia and all fibrillar associates except enlarged transverse ribbons, which extend anteriorly and inwards to support the cytopharynx. Other similarities between the buetschliids and Enchelydium are the conspicuous rough endoplasmic reticulum and abundant sausage-like vesicles in the oral region. As in other haptorids, Enchelydium has two types of toxicysts and one type of mucocyst. These observations strongly suggest that Enchelydium belongs to the ancestral stock of both the Haptorida and the Archistomatida. The similarities in the somatic and oral infraciliature and ultrastructure of the Haptorida and the Archistomatida suggest that they belong to the same subclass, Haptoria Corliss, 1974.     

Etude Ultrastructurale du CiliéKuklikophrya dragescoi gen. n., sp. n.*

SYNOPSIS The cortical infraciliature of Kuklikophrya dragescoi gen. n., sp. n. is composed of double kinetosomes. Each kinetosome has transverse fibers. The anterior transverse fibers are associated with a sheet of dense material and the posterior transverse fibers are directed toward the posterior part of the body. The posterior kinetosome of a pair has only a short protuberance in the position of the kinetosomal fiber. The cortex has a well developed alveolar layer and a thick ecto-endoplasmic boundary. A distinctive characteristic of the buccal ciliature is the circumoral ciliature whose infraciliature is made up of pairs of cilia-bearing kinetosomes. The antero-posterior polarity of the paroral segment is in inverse relationship to that of the remaining ciliature of the organism. The adoral and preoral ciliary organelles consist of 2 rows of kinetosomes, each of which bears postciliary fibers. A frame of nematodesmata surrounds the cytopharynx which is supported by microtubular bands which impart to it a very specific laminated appearance. The “phagoplasm” is formed by “vermicelli”-like vesicles. The micronucleus is found in the perinuclear area of the macronucleus.     

The Ultrastructure of Chaenea teres and an Analysis of the Phylogeny of the Haptorid Ciliates

Chaenea teres has typical haptorid ultrastructure. The somatic monokinetid has two transverse microtubular ribbons, an overlapping postciliary microtubular ribbon, and a laterally directed kinetodesmal fiber. The evered cytopharynx forms a dome at the apical end of the cell. The base of the dome is surrounded by oral dikinetids. The left, anterior kinetosome of the oral pair is not ciliated and has a transverse microtubular ribbon, a nematodesmata and a single postciliary microtubule. The right, posterior kinetosome is ciliated and has only postciliary microtubules. The kinetosomes at the anterior ends of the somatic kinetics are close together and their transverse microtubules and nematodesmata contribute to the support of the cytopharynx. The transverse microtubules of these oralized somatic kinetosomes, together with those from the oral dikinetids, line the cytopharynx. Accessory or bulge microtubules arise perpendicular to the transverse microtubules. A dorsal brush of three kineties of clavate cilia is found on the cell surface just posterior to the oral region. Mucocysts and a single type of toxicyst are present. The toxicysts are confined to the oral region. There are multiple ovoid macronuclei that stain weakly. Micronuclei were not observed. Cladistic analysis indicates the Chaenea may be most closely related to Fuscheria and Acropisthium. The cladistic analysis also suggests that existing taxonomies of the subclass Haptoria need to be revised. We propose some modifications to Foissner & Foissner's classification that include transferring Helicoprorodon, Actinobolina, the buetschiliids, and the balantidiids to the order Haptorida and recognizing the close relationship between pleurostomes and spathidiids.     

Ultrastructure of the Oral Apparatus of Mesodinium rubrum from Korea

Mesodinium rubrum Lohmann is a photosynthetic marine ciliate that has functional chloroplasts of cryptophyte origin. Little is known about the oral ultrastructure of M. rubrum compared with several reports on the sequestration of nuclei and plastids from prey organisms, such as Geminigera cryophila and Teleaulax species. Here, we describe the fine structure of the oral apparatus of a M. rubrum strain from Gomso Bay, Korea. The cytopharynx was cone‐shaped and supported by 20–22 ribbons of triplet microtubules. At the anterior end of the cytopharynx, an annulus anchored small cylinders composed of 11 microtubules. The small cylinders were spaced at regular intervals, each reinforced by one set of the triplet microtubules. At the opening of the cytostome, larger 14‐membered microtubular cylinders were set adjacent to the small, 11‐membered microtubular cylinders, each pair surrounded by separate membranes, however, only the large cylinders extended into the oral tentacles. There were 20–22 oral tentacles each having one to five extrusomes at its tip. At the anterior end of the oral apparatus, microtubular bands supporting the cytostome curved posteriad, extending beneath the cell cortex to the kinetosomes of the somatic cirri. The microtubular bands were connected by striated fibers and originated from kinetosomes anchored by fibers. Each cirrus consisted of eight cilia associated with 16 kinetosomes. The ultrastructure of M. rubrum from Korea provides information useful for taxonomic characterization of the genus Mesodinium and relevant to developing a better understanding of the acquisition of foreign organelles through phagocytosis by M. rubrum.     

The Ultrastructure of Zosterodasys agamalievi (Ciliophora: Synhymeniida)

ABSTRACT. The cell surface of the synhymeniid ciliate, Zosterodasys agamalievi , consists of shallow kinetal grooves separated by low cortical ridges. Numerous electron-opaque bodies are located in the cortical ridges, inside the kinetal grooves, and are distributed in parallel rows between adjacent kineties. Well-developed alveoli are present beneath the cell surface membrane. Zosterodasys agamalievi has a single micronucleus and a homomerous macronucleus. The infraciliature of the somatic monokinetid consists of an anteriorly-directed kinetodesmal fiber, a well-developed divergent postciliary microtubular ribbon, radially-oriented transverse microtubules, and a short striated rootlet, which extends anteriorly from the base of the kinetosome into the cell. Zosterodasys agamalievi has a perioral band of paired cilia, the synhymenium, that winds obliquely across the ventral surface of the body, just posterior to the cytostome. The infraciliature of the anterior kinetosome of the synhymenium consists of two postciliary microtubules; a well-developed, divergent post-ciliary ribbon of microtubules and a short kinetodesmal fiber are associated with the posterior kinetosome. The cytopharynx is supported by 14-16 nematodesmata which are capped distally by a capitulum. The cytopharynx is bound proximally by a fibrous sheath and is lined by radially-arranged microtubular ribbons. No obvious oral ciliature is present.     

A Reexamination of the Ultrastructure of Didinium nasutum and a Reanalysis of the Phylogeny of the Haptorid Ciliates

ABSTRACT. The cilia of Didinium nasutum are restricted to two girdles encircling the cell. Each row of cilia in both girdles is made up of two to three anterior pairs of kinetosomes followed by several single kinetosomes. Each single kinetosome has two sets of transverse microtubules, an overlapping postciliary microtubular ribbon, and a laterally directed kinetodesmal fiber. The pairs of kinetosomes are homologous to the oral dikinetids of other haptorians: the nonciliated kinetosome of the pair has a transverse microtubular ribbon that extends to line the membrane of the proboscis, a single short postciliary microtubule, and a nematodesma; the ciliated kinetosome has a ribbon of postciliary microtubules and two sets of transverse microtubules. The presence of these characters in Didinium invalidates Leipe & Hausmann's conclusion that the Didiniidae should be removed from the subclass that contains the other haptorians (Leipe, D. D. & Hausumann, K. 1989. Somatic infraciliature of the haptorid ciliate Homalozoon vermiculare (Kinetofragminophora, Gymnostomata) Ditransversalia n. subcl. and phylogenetic implications. J. Protozool. , 36 :280–289). In light of this, the justification for a subclass Ditransversalia is challenged and shown to be unnecessary.     

Structure of the flagellar apparatus of heterotrophic flagellate Klosteria bodomorphis Nikolaev et al., 2003 (Kinetoplastea Excavata)

The structure of the flagellar apparatus of excavate flagellate Klosteria bodomorphis was considered. Two naked heterodynamic flagella covered with a dense layer of glycocalyx emerge from a single flagellar pocket. The kinetosomes are parallel or at an acute angle to each other. The dorsal and ventral rootlets run from the kinetosomes and produce dorsal and ventral bands which are not connected to each other. The MTR band begins in the wall of the flagellar pocket. The long cytopharynx is reinforced with an MTR band and additional microtubules. A small fibril and a horseshoe-shaped structure lie in the anterior part of the cytopharynx. The vesicular nucleus and Golgi apparatus have the typical structure. The mitochondrion has discoid cristae. The kinetoplast as a compact formation was not found. The similarity between K. bodomorphis and other free-living kinetoplastids is discussed.     

武昌六前鞭虫胞器超微结构的研究

对武昌六前鞭虫胞器的超微结构进行了观察,发现R鞭毛复合体的内下方有分散的微管,两根R鞭毛复合体之间和外方具少量的粗面内质网,而虫体周边分布较多.粗面内质同外周被发达的微管.生毛体与胞核之间有胞咽和小盾结构.胞质中有较多的食物泡,未见到线粒体、高尔基体和表膜下微管结构.另外对粗面内质网的结构、功能以及种的鉴定等方面也作了讨论.       

Structure of the flagellar apparatus in the bacteriotrophic flagellate Parabodo nitrophilus Skuja, 1948 (Kinetoplastea Excavata)

The structure of the flagellar apparatus in the excavate flagellate Parabodo nitrophilus Skuja has been studied. Two smooth heterodynamic flagella emerge from the bottom of the flagellar apparatus. The kinetosomes connected by their proximal ends lie under an acute angle to each other and bear against the plate on the anteior wall of kinetoplast. The dorsal and ventral rootlets emerge from the kinetosomes and are transformed into dorsal and ventral bands. The latter accompanies the posterior flagellum. The MTR band begins inside the wall of the flagellar pocket. The upper part of the cytopharynx is armored by MTR and FAS bands, cross-banded fibril and structure, and additional microtubules. The MTR band and three additional microtubules surround the bottom part of cytopharynx. The mitochondrium contains compact kinetoplast and discoid cristae. The resemblance of Parabodo nitrophilus with other free-living kinetoplastids is discussed.     

Ultrastructure of Prorodon (Ciliophora, Prostomatida) Ii. Oral Cortex and Phylogenetic Conclusions

ABSTRACT. The ultrastructure of the oral region and the ultrastructural architecture of the basket of Prorodon aklitolophon and Prorodon teres are described. the oral region of Prorodon consists of: 1) A circumoral kinety at the anterior pole of the cell surrounding the typically slit-shaped cytostomial funnel. This kinety is composed of inversely oriented dikinetids in which both kinetosomes are ciliated and are associated with a very short postciliary microtubular ribbon and a few transverse microtubules; 2) Three brush rows aligned in parallel and extended meridionally in the anterior part of the cell. the individual brush rows consist of dikinetids, but in contrast to the dikinetids around the cytopharynx they are not inverted and only the anterior kinetosomes bear specialized short brush cilia and are associated with a divergent-tangential transverse microtubular ribbon. the posterior kinetosome is non-ciliated and bears a prominent convergent postciliary microtubular ribbon. Schematized dikinetid patterns of both oral regions of Prorodon are provided. In addition, a three-dimensional reconstruction of the basket of the genus Prorodon based on serial thin sections is presented. A phylogenetic tree, mainly based on stomatogenic data, is given to show the phylogenetic relationships of some prostomatid genera as well as the hypothesized sistergroup relationship of colpodid and prostomatid ciliates.     

Morphogenesis of infraciliature in the entodiniomorphid ciliate Eudiplodinium maggii

The morphogenesis of ciliary zones has been studied in the ciliate Eudiplodinium maggi which has a vestigial somatic infraciliature consisting of subcortical barren kinetosomes. These replicate and migrate into the subequatorial ciliary anlagen of the dividing cells. The kinetid pattern of the barren kinetosomes changes sequentially to that of the ciliary zones. Postciliary and transverse microtubules are derived from basal and cortically directed microtubules while a dense spur coincides with the origin of the kinetodesma. All kinetics produce potential cytopharyngeal components. Nematodesmata originate in granular subkinetosomal dense plates, while two of the three types of cytopharyngeal ribbon are formed from tansverse microtubules. A spatial selectivity ensures that these components extend only from specific kinetids. It is concluded that 91) morphogenesis of the intricate cytoskeletal network of infraciliature involves a “pattern generator” in the vestigial somatic kinetids; and 92) entodiniomorph stomatogenesis in not truly apokinetal but is more like the telokinetal process of related ciliates.     

Evidence for Hymenostome Affinities in an Apostome Ciliate

The functional mouth of exuviotrophic apostome ciltates appears only after an elaborate metamorphosis that begins at the onset of the molting of their crustacean hosts. In the tomite. a non-feeding migratory stage, a mid-ventrai depression at the origin of kineties x, y and z has been misidentified as the cytostome. Studies of fine structure and morphogenesis identify the true but nonfunctional cytostome—the subapiral lateral canal —and the falciform and ogival fields as the adoral ciliature. The anterior row of barren kinetosomes that parallels on the right the anterior third of the lateral canal is actually the infraciliature of a paroral. 2 rows of barren staggered kinetosomes. The canal itself is a narrow tube, its walls partially lined with microtubules. It begins 2–3 μm from the apex of the body and passes between falciform field 9 and the ogival field to end near the end of the ogival field. The fine structure of the infraciliature of the falciform and ogival fields differs markedly from that of the somatic kineties. In the host's early pre-molt stages, the paroral migrates across the ventral surface of the encysted phoront and is accompanied by the microtubules of the lateral canal. The anterior end of falciform field 9 disorganizes into scattered kinetosomes, the trophont's anterior field of kinetosomes, but the posterior end migrates in an arc across the anterior ventral surface and remains as kinety a located near the angle where kinety 1 sharply par ra continues posteriad ind dorsad to the posterior limit of the extended cytostome. At the end of metamorphosis it sinks into The cytoplasm and disappears. The completion of the extended cytostome, the functional mouth, marks the termination of the microstome-macrostome transformation. The fine structure of the infraciliature and microtubular elements making up the macrostome and the evocation of the microstome-macrostome transformation in the presence of specific foods suggest that apostome ciliates any more properly be a suborder of Hymenostomatida rather than a subclass of Oligohymenophorea.     

Ultrastructure of the Somatic and Buccal Cortex of the Tetrahymenine Hymenostome Glaucoma chattoni

SYNOPSIS The membranes, epiplasm, and fiber systems are described in the somatic cortex of Glaucoma chattoni strain HZ-1. Kinetodesmal fibers, postciliary and transverse microtubular ribbons, basal microtubules, transverse fibers and transverse accessory material are associated with kinetosomes. Longitudinal microtubular ribbons and mitochondria occur interkinetally. In the buccal cortex, the membranes, epiplasm and fibers of the 3 membranelles, the paroral kinety, the ribbed wall, and the cytostome are described. Comparisons between G. chattoni and other ciliates reveal ultrastructural differences of possible systematic significance. In the somatic cortex of this and other tetrahymenines. Iongitudinal microtubular ribbons and basal microtubules occur concurrently. In the buccal cortex, alveoli are absent in tetrahymenine membranelles. A table is presented of the fiber systems associated with single somatic kinetosomes of various ciliates whose cortical ultrastructure has been studied to date.     

Ultrastructure of the Somatic Cortex of the Gymnostome Ciliate Spathidium spathula (O. F. M.)1

The somatic cortex of Spathidium spathula is described ultrastructurally. The pellicle consists of an outer membrane and an underlying alveolar system. Numerous membrane-bound mucocysts and spherical electron-opaque bodies have similar circular sites of attachment to the outer membrane. Below these are a microfibrillar zone and an underlying region of rough ER. Mitochondria are lined up under the rough ER in longitudinal cortical ridges. Parasomal sacs are found near the basal bodies and are associated with cytoplasmic membranous sacs. Various microtubular and fiber systems are associated with single basal bodies: (1) a short kinetodesmal fiber; (2) two transverse microtubular ribbons and a transverse fiber; (3) a postciliary microtubular ribbon, initially sandwiched by two fibers, which gives rise to longitudinal subpellicular microtubules extending posteriorly for a distance of some four or five basal bodies; and (4) a system of overlapping subkinetal microtubules. A three-dimensional reconstruction is included. The somatic cortex of S spathula is similar to that reported for other Haptorida of the ciliate subclass Gymnostomata.     

Buccal and Somatic Infraciliature of Lagynus elegans (Engelmann, 1862) Quennersted, 1867 (Ciliophora, Prostomatea): Remarks on its Systematic Position

The somatic and buccal infraciliature of Lagynus elegans are described, and aspects of its division and conjugation are reported. Its somatic infraciliature is made up of 37–46 meridianal kineties composed of isolated kinetosomes that have thick and long kinetodesmal fibers. In the anterior zone of the cell, the circumoral infraciliature can be observed: it is composed of short, slightly oblique kinetal segments, which are formed of three kinetosomes each. The brosse of this species consists of 3 or 4 groups that possess 4 to 6 ciliated kinetosomes each; these kinetosomes lack kinetodesmal fibers. On the apical pole of the cell, surrounding the oral opening, a crown of nematodesmata is observed; these nematodesmata are connected to each other by a fibrillar structure. Taking into account these features, we propose that this genus be transferred from the order Prostomatida to a new family, Lagynidae, of the order Prorodontida.     

Morphologie,Infraciliatur und Ökologie der limnischen Tintinnina: Tintinnidium fluviatile Stein,Tintinnidium pusillum Entz,Tintinnopsis cylindrata Daday und Codonella cratera (Leidy) (Ciliophora,Polyhymenophora)*

Synopsis. Structure, infraciliature, and ecology of 4 fresh-water Tintinnina were investigated. The lorica of Tintinnidium fluviatile is gelatinous, fragile, and contains some agglutinated material mainly of biologic origin. Its infraciliature consists of ? 10 kineties. with kinetosomes arranged in pairs. Only one basal body of a pair is ciliated, except for the uppermost 1–4 pairs which have 2 slightly elongated cilia. In Tintinnidium fluviatile. Tintinnidium pusillum, and Tintinnopsis cylindrata there are 2 prominent ventral organelles. The lorica of T. pusillum is gelatinous and coated with much agglutinated material of biologic and nonbiologic origin. Its infraciliature is similar to that of T. fluviatile, but the uppermost pair of kinetosomes has elongated cilia. The firm loricae of T. cylindrata and Codonella cratera are, built mainly of sharp-cornered structures. The infraciliature of T. cylindrata is composed of ? 10 kineties with kinetosomes not arranged in pairs. The infraciliature of C. cratera consists of ? 32 kineties, in some of which the kinetosomes are paired, e.g. ventral kinety, and in others not paired, e.g. cilia of the very prominent lateral field and of the other somatic kineties. The uppermost kinetosomes of each somatic kinety are paired and have elongated cilia. In addition, there is an unusual ventro-lateral kinety. The oral apparatus consists of adoral membranelles and a paroral membrane. The membranelles that enter the praecral cavity are very elongate, a feature perhaps unique to Polyhymenophora. The fibrillar system consists of a prominent praeoral ring formed by fibrils extending from the adoral membranelles. A finely meshed silverline system extends over the entire cell. A review of the ecology of the fresh-water Tintinnina indicated that water temperature seems to be the most essential ecologic factor. The systematic position of the Tintinnina is discussed in light of their infraciliature. It is concluded that these organisms are most closely related to Oligotrichina, and probably to Heterotrichina.