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141.
In the course of a survey of the history of the study of Heliconiinae, particularly their biology, in the eighteenth and nineteenth centuries it is shown that Heliconius nigromarginatus (Goeze) and H. pallescens (Goeze) are nomina oblita , and that H. cinereofuscus (Goeze) is not, as always supposed, a species in its own right. A new name is proposed for H. melpomene cybele (Cramer). The origin and application of some of Linnaeus' names is discussed.
Illustrations of Heliconius by Seba, Clerck, Petiver and Cramer show that three species, melpomene, erato and doris have been polymorphic at least since the middle of the eighteenth century.
The Indo-Australian genus Cethosia should probably be included in the Heliconiinae.  相似文献   
142.
SYNOPSIS. Meridian ranges and contractile vacuole pore patterns were determined for 36 strains of Tetrahymena pyriformis, including most of the “classic” amicronucleate and micronucleate strains used by many investigators, plus a dozen other strains not previously characterized with respect to these two morphological features. Uniform axenic culturing and staining techniques were employed. Meridian ranges and modes are analyzed with strain-by-strain comparisons to the reports of previous investigators. The overall inclusive range of the 36 strains was 15–25 meridians. Modes for individual strains varied from 16 to 23. Broader ranges and, especially, higher modes and higher limits are recorded than those reported by Corliss (1953) for strains grown in bacterized hay cultures. Two postoral meridians are characteristic, although a single individual having only one and a few having three postorals were observed. Three postorals were found only in those strains having the higher number of total meridians. A few individuals, showing an anterior half or a posterior half of a bipolar meridian missing, indicate a possible explanation of how a single dividing individual could produce a proter and an opisthe differing in the total number of meridians. Meridian ranges of individual strains do not overlap each other in all cases, but they do constitute a progressively overlapping series which does not warrant taxonomic separation of strains at either extreme from each other. Contractile vacuole pores varied from 1 to 3, with 2 pores (1 each in meridians 5 and 6) being characteristic of 22 of the strains. The 2-pore 6-7 pattern was modal for 8 of the strains. Presence of 3 pores (in 5, 6 and 7) was typical of only 2 strains, but 3 pores were found occasionally. Another pattern of 3 pores (in 6, 7 and 8) was observed occasionally in 10 strains. Double pores (in 6 and 7 or 7 and 8) and the triple pore patterns were observed only in the strains having the highest total number of meridians. These variations are not considered adequate justification for taxonomic separation. Strains Ki and Aq are affirmed to be T. pyriformis. Strains V1 PP and V, formerly regarded as strains of T. vorax, are considered to be T. pyriformis, supporting the view of Shaw and Williams (1963).  相似文献   
143.
SYNOPSIS. Two isolates ("A" and "B") of Trypanosoma lewisi from the same rat stock source were serially transferred in calorically-restricted mice supplemented daily with normal rat serum. The "A" strain was transferred consecutively through 300 mice over a period of more than 3 years and was voluntarily discontinued. The "B" strain died out spontaneously after 43 consecutive passages in mice. The developmental histories of these 2 isolates were analyzed and compared with respect to duration of the parasitemic period, interval to the next subsequent passage in mice, day of death of each host animal, proportion of host animals that died, intensity of parasitemia in mouse tail blood, interval required for development of the observed maximal parasitemia, and duration of maximal parasitemia.
"A" appeared to have become progressively adapted to the mouse as judged by a decrease in parasitemic period with successive transfer associated with a progressive increase in trypanosome population, and declines in the interval required for development of the observed maximal parasitemia and in the duration of this maximal response. There did not appear to be any correlation of the percentage of animals that died with any other factor. The "B" strain did not appear to have adapted itself to mice as judged by the foregoing criteria.  相似文献   
144.
145.
SYNOPSIS. Eimeria scholtysecki n. sp. is described from Ord's kangaroo rat Dipodomys ordii. The sporulated oocysts are broadly ovoid to ellipsoid, averaging 24.6 by 19.6 μ. A polar granule is present. A micropyle and oocyst residuum are absent. The ovoid sporocysts average 12.1 by 8.0 μ, and have small, flattened Stieda bodies. The distinctive sporocyst residuum is composed of coarse granules. The mean prepatent period was 8.2 days. Five inoculated rats apparently became reinfected and discharged oocysts for 30 days or more.  相似文献   
146.
SYNOPSIS. A sequence of developmental stages of Plistophora hyphessobryconis Schaperclaus, a microsporidian protozoan parasite of the muscular tissue of several species of freshwater fishes, was studied with the electron microscope. The youngest stages observed, ca. 4 × 2 μ, have a single nucleus and their plasm contains only ergastoplasmic lamellae and ribosomes. They are surrounded by a halo of lysed host tissue. They increase in volume to become large sporonts with a great number of nuclei and a thick, 2-layered membrane. Thru schizogony, a corresponding number of sporoblasts is produced within this pansporoblast membrane. Sporoblasts start to develop a thick spore membrane, and a number of smooth-membraned vesicles appear in the plasm. These vesicles fuse to make the outer membrane of the filament. Later, its inner structures originate—the axial electron-dense substance, filling the hollow lumen of the filament, and a middle, electron-transparent layer. The structure of the filament is discussed in relation to its function and with regard to the findings of other authors. The polaroplast is a laminated structure, originating possibly by transformation of endoplasmic reticulum; the polar cap forms its apical part. The cap is also lamellar; its substance reaches into the lumen of the filament for a certain distance. No micropyle was discovered in the shell; the filament is fastened to the polar cap. These observations on microsporidian development and on the structure of their spores are compared with similar data on myxosporidian species. Such a comparison speaks clearly in favor of the complete taxonomic separation of the Microsporidea from the Myxosporidea, the latter being quite different also from other sporozoa sensu lato.  相似文献   
147.
Excitation-Contraction Coupling in Crayfish   总被引:8,自引:0,他引:8  
High-sensitivity recording techniques demonstrate a continuousrelation between the onset and magnitude ot tension and themembrane depolarization that is induced by increasing K in thebathing medium or by intracellularly applied outward currents.This finding is not consistent with the mechanism of signallinge-c coupling by electrotonic spread of a "critical" depolarizationinward along the membrane of the transverse tubular system.It is in accord, however, with the channelled current mechanismthat is based on the known anion-permselectivity of the membranein the terminals of the TTS. The channelled-current model alsopredicts a direct role of Cl and a possible interaction betweenCa and CI in e-c coupling. The initiation and maintenance oftension as well as its magnitude, are in fact dependent uponthe concentrations of Ca and Cl in the medium. Thus, both thesignalling to, and the activation of, the contractile systemappear to be performed by a flow of current in the loop: cellmembrane – cell interior – TTS membrane –TTS channels – exterior, as is envisaged in the channelled-currentmodel of e-c coupling.  相似文献   
148.
Miniature collar-type transmitters originally designed by W.W. Cochran, Illinois, were adapted for use on timber wolves(Canis lupus sp.) in east-central Ontario. Wild timber wolveswere captured in steel traps, restrained with a forked stick,fitted with radio-collars and released at point of capture.Receivers were adapted for use in trucks, airplanes, and forwalking in rough bush country. Maximum ranges were 3.2 km withground and 9.6 km with aircraft receivers. A preadult femaletagged in July, 1964, and a lactating adult female tagged inJune, 1965, were tracked intermittently for 5.5 and 2.5 months,respectively. Tracking periods for six other animals of bothsexes, ranging in age from pups to adults, varied from 2 daysto 4 months. The lactating female and her associated pack regularlyreturned to three preferred "resting sites" for various periodsduring July and August. Preferred areas were well drained, semi-open,mixed conifer-hardwood stands in close proximity to swamps orbeaver ponds. The preadult female ranged in an area frequentedby a pack, but frequently remained independent of it. A preadultmale, tagged in the same region, wandered over a slightly largerarea than the female. Tagged animals were active throughoutall periods of the day or night. Activity increased slightlyduring the early evening hours. There was a slight correlationbetween weather conditions and patterns of behavior and activity.Apparently, tagged individuals were quickly accepted by othermembers of the pack.  相似文献   
149.
An ultrastructural study of life cycle stages of Pneumocystis carinii in infected rat lungs in situ was undertaken utilizing 8 different modes of fixation. Three of the fixatives employed gave good fixation of cysts and intracystic bodies, but for the trophic forms fixation was only fair. Both the trophic forms and intracystic bodies have nuclear pores. The mitochondria of the organism have cristac that appear lamellar. One of the fixation modes revealed a thin, electron-dense layer on the outer surface of the cell wall, a "fuzzy coat" that had not been described previously. This material appears to mediate tight adhesion of trophic forms with other trophic forms, cysts, and with pneumocytcs of the lung alveolus.  相似文献   
150.
Nectar-feeding birds are prominent in many parts of the world, and vary with respect to body size. Despite the availability of considerable morphometric data, few concerted efforts have been made to assess the influence of attributes such as mass, wing length and leg morphology upon the speed, acceleration, mode and energetic cost of movement by birds between flowers when foraging for nectar. This review attempts to consolidate and interpret available data and highlight areas where further investigations appear warranted. Australian honeyeaters are generally larger, and American hummingbirds smaller, than Hawaiian honeycreepers and sunbirds of Africa or Asia. Sunbirds, honeyeaters and honeycreepers generally perch while extracting nectar from flowers. Hummingbirds usually hover, apparently because suitable perches close to flowers are lacking, and not because hovering increases the speed at which flowers can be visited. Honeyeaters move from one flower to another at speeds that are at least as great as those for hummingbirds. Most passerine nectarivores need to ingest more nectar per day than hummingbirds in order to maintain energy balance, some species devoting more than 60% of the day to foraging. The major consequence of reduced foraging activity by hummingbirds, which spend only 5–30% of the day in this manner, appears to be male emancipation from nest construction and care of offspring. Large nectarivores have a greater capacity to store surplus food and to fast than smaller birds, and so can take advantage of short-lived peaks in nectar abundance. Nectarivores such as honeyeaters should therefore be favoured by the rapid diurnal changes in nectar availability which are characteristic of many Australian and African habitats. Body mass also determines the likely access to rich sources of nectar through size-related interspecific dominance hierarchies. In all families, larger species tend to monopolize the most rewarding nectar supplies, forcing smaller subordinate species to use poorer, more scattered sources. Within particular species, males usually have longer wings and greater masses than females. These variations imply that the two sexes differ with regard to their foraging ecology, although few supporting data are currently available.  相似文献   
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