The ultrastructure of germinal beds in the ovary of Gerrhonotus coeruleus (Reptilia: Anguidae)

A study of ovarian structure in adult Alligator Lizards (Gerrhonotus coeruleus) was conducted by light microscopy and transmission electron microscopy. Particular attention was directed to characterizing the ultrastructure of germ-line cells, prior to follicle formation. General ovarian structure in this lizard is similar to that of other lizards. The paired organs are hollow, thin-walled sacs containing follicles in roughly 3 to 4 size classes. Ovarian germinal tissue consists of oogonia (diploid cells which divide mitotically) and oocytes (meiotic cells), intermixed with ovarian surface epithelial cells. Germ cells reside in two dorsal patches of epithelium per ovary (germinal beds), as is common in lizards. Oogonia in interphase show a highly dispersed chromatin pattern. Within oogonia cytoplasm, Golgi complexes are scarce, rough endoplasmic reticulum is absent, and lipid droplets are rare. Ribosomes are scattered in small clusters. Small, round vesicles are common in all oogonia; glycogen-like granules are present in some. Mitochondria form a juxtanuclear mass within which groups of several mitochondria surround a dense granule. “Nuage” granules also are found unassociated with mitochondria. Oocytes are present in stages of meiotic prophase up to diplotene. Synaptinemal complexes are seen in several (pachytene) cells. The cytoplasm of oocytes differs from that of oogonia in that mitochondria do not form groups, and nuage and glycogen are absent, whereas small round vesicles and large irregular vesicles are common. The ultrastructural similarities in germ cells of a reptile as compared to those of other vertebrates strengthens the notion that germ-line cells possess (or lack) qualities related to the undifferentiated state of these cells.     

Observations on thermoregulation in the western slender glass lizard, Ophisaurus attenuatus attenuatus (Sauria: Anguidae)

Based upon thermocouple implantation, thermal preferenda and voluntary maxima for the head and body were studied in three individuals of Ophisaurus attenuatus attenuatus collected in Texas. Calculated grouped data for the head and body mean preferred temperature were 31.2°C (range 29.O° -34.7°C) and 31.8°C (range 30.3° -34.5°C) respectively. Gaping or panting were found to be absent in the O. a. attenuatus examined in this study.     

Tail regeneration in the lizards Anguis fragilis and Lacerta dugesii

Rates of tail regeneration in the Madeira wall lizard ( Lacerta dugesii ) and the slow-worm ( Anguis fragilis ) were studied.
L. dugesii regenerates very rapidly, the new tail sometimes attaining a maximum rate of growth of 2'6 mm a day during the fifth week after autotomy. By the twelfth week 90% of the original tail length has been replaced. Average regeneration rates of samples of lizards were reduced after repeated autotomies, but our investigation of this problem was probably complicated by another factor, the amount of tail lost, and is inconclusive.
The tip of the regenerate grows more rapidly than the rest; no elongation occurs at its cranial aspect.
Anguis , even when kept at 27°C, regenerates its tail very slowly, the best performance observed being a new tail of 5 mm after 14 weeks. The longest natural regenerate seen (16 mm) may have taken several years to produce in the wild.
The histological features of regeneration in Anguis are basically similar to those in other lizards. The new osteoderms are formed entirely in the subepidermal tissues but have a regular relationship with the scales. Some nerve fibres are regenerated with the ependymal tube.
The scales on the lizard's regenerating tail develop in a different manner from those in the lizard embryo and show suggestive resemblances to mammalian hairs.     

Observations on the endogenous stages of Eimeria crandallis in domestic lambs (Ovis aries)

Lambs reared coccidia-free were inoculated orally with various numbers of sporulated oocysts of E. crandallis and were killed between 1 and 22 days after inoculation; tissues were examined histologically. Sporozoites were seen 1, 2 and 3 days after inoculation (DAI) in crypt epithelial cells in the mid-jejunum. Infected cells migrated into the lamina propria where the parasite within them developed into a firstgeneration meront containing about 250,000 merozoites at 10 DAI. A second generation of meronts was seen at 10–12 DAI, each containing up to about 10 merozoites, situated mainly at the bases of crypts in the jejunum and ileum but also in the caecum. From 11 DAI pro-gamonts were seen which were enveloped by the host cell nucleus and which divided in synchrony with the host cell for an undetermined number of generations. Mature gamonts began to develop from them by 16 DAI. Oocyst output began at 16 DAI and rose to a peak at about 22 DAI. Up to 10⁸ oocysts were produced per oocyst inoculated. They showed wide variation in size and colour.     

DNA synthesis decline involved in the developmental arrest of the limb buds in the embryos of the slow worm, Anguis fragilis (L.).

The present study was carried out to try and detect the biochemical mechanism involved in the developmental arrest of the limb bud in a serpentiform Reptile. Autoradiograpy, following tritiated thymidine incorporation, in embryos of the slow-worm (Anguis fragilis, L.) reveals a strong decrease in the rate of DNA synthesis in the mesodermal cells of the limb bud, after the degeneration of the apical ectodermal ridge (AER); the curve (a function of Gompertz) visualizing this decline shows that the drop in DNA synthesis becomes accentuated just after the degeneration of the AER. This decrease precedes the reduction of the mitotic index, the cell degeneration in the mesoderm and the other regressive changes occurring in the limb bud; it thus appears as the main causative factor of the developmental arrest of the limb bud. Furthermore, these results suggest that one of the functions of the AER would be to maintain a high level of DNA synthesis in the mesoderm underlying the AER in a normal limb bud.     

Helminths of the San Diego alligator lizard, (Gerrhonotus multicarinatus webbi) (Anguidae)

Necropsy of 96 specimens of the San Diego alligator lizard (Gerrhonotus multicarinatus webbi) from Los Angeles County, California (USA) revealed the presence of two nematodes (Physaloptera sp. and Oswaldocruzia pipiens) and a cestode (Oochoristica sp.). Both O. pipiens and Oochoristica sp. represent new host records. Prevalence of helminth infection (all species) was only 4/96 (4%) indicating the lack of a helminth community and a depauperate helminth fauna in this host.     

Observations on the activity and thermoregulation of the tuatara,Sphenodon punctatus (Reptilia: Rhynchocephalia), on Stephens Island

Abstract

Observations on Stephens Island, Cook Strait, in December 1978 show that although the tuatara is generally most active at night, many animals spend much of the day at or beyond burrow entrances, apparently to increase their body temperature. During the day, tuataras tend to move further from burrows which are under shaded forest than from those in open pasture. By day, mean body temperatures (±SE) ranged from 17.2±0.5°C in forest shade to 24.6±1.1°C in full sunlight; the maximum body temperature recorded was 26.3°C. The significance of these observations is discussed.     

Cytochemical Observations of Gemmule Development in Eunapius fragilis (Leidy): Porifera; Spongillidae

The cytology and cytochemistry of gemule formation in the freshwater sponge Eunapius fragilis (Leidy) is investigated. The aggregation of ameboid cells which initiates gemmulation is composed of three distinct cell types, two of these fitting the morphological criteria of the archeocyte class. The third cell type, the granular cell, is a differentiated cell type which undergoes cytolysis during gem-mule coat synthesis. Following early polarisation of the aggregate into an internal reproductive area and a peripheral coat region, a structurally and chemically heterogeneous gemmule coat is synthesis-ed. The coat is formed through secretory activities involving several cell types including, possibly, the internal endothelium. The coat is composed of collagenous fibers embedded in a matrix of varying degrees of density–showing close structural and cytochemical similarities to vertebrate chondroid tissue. Vitelline platelets of thesocytes of E. fragilis do not cytochemically resemble any previously reported vitelline inclusions from other sponges. Outer valves of the platelets contain components stained by basic dyes at acidic pH which are not extracted by RNase. Distinct differences in developmental processes and morphological–including cytochemical–characteristics of gemmules of different spongillid species are apparent.     

Eimeria ornata N. Sp. (Apicomplexa: Eimeriidae) from the Ornate Box Turtle, Terrapene ornata ornata (Reptilia: Testudines), in Texas

Eimeria ornata n. sp. is described from the feces of 6/16 (37.5%) ornate box turtles, Terrapene ornata ornata , in northcentral Texas. Endogenously sporulated oocysts are ellipsoid 17.9 × 15.7(16-21 × 14-18) μm, with a thin, single-layered wall; shape index 1.14 (1.0-1.3). A micropyle is absent but a polar granule was present in one third of the oocysts. An oocyst residuum was present, consisting of numerous small globules situated either in a distinct mass or scattered within the oocyst. The sporocysts are elongate, 11.1 × 5.4 (9-13 × 5-6) μm, with an indistinct Stieda body at 1 pole. A sporocyst residuum is present, consisting either as a compact mass or as scattered granules. The sporozoites are elongate, 9.5 × 2.0 (8-12 × 2) μm, in situ, with spherical anterior and posterior refractile bodies. The new species is distinguished from the similar Eimeria carri Ernst & Forrester, 1973, from eastern box turtles, T. Carolina , by slight differences in oocyst morphology and endogenous sporulation.     

Notes on reptiles of Tunesia. VII. Observations on a double-headed snake Natrix (Reptilia: Colubridae)

A case of a double-headed Viperine Snake Natrix maura (Linné, 1758) hatching is reported. Its two heads are side by side, about equally and perfectly developed and the neck is dual for the 8 first vertebras. Two post-pharyngeal fistulas and dissymetries in the cephalic markings and scales are noted. The origin of such an anterior dichtomy is discussed.