This paper describes the fine structure of the egg shell of the neuropteran Chrysopa carnea by transmission and scanning electron microscopy. Particular attention has been directed to the structure of the micropylar area and chorion. The micropylar region consists of a circular area with 30 semicircular channels, each corresponding to a micropylar orifice, localized at the apical pole of the egg. The endochorion of C. carnea consists of plurilaminar layers, each made up of subunits periodically arranged, parallel to the egg surface.
SUMMARY In the Urodele amphibians the neurohypophysis shows different degrees of development. In Proteus, Ambystoma and Hydromantes, for instance, it consists of a thin lamina and the median eminence is poorly differentiated. In contrast, Triturus and Salamandra posses a thicker pars nervosa, and the median eminence is characterized by a functional stratification which does not substantially differ from that of other tetrapcds, e.g. the Anuran amphibians. In the Urodele neurohypophysis, inspection at the ultrastructural level reveals some relatively uniform features within the same group, e.g. as regards tanycytes, while other components may differ considerably between groups, such as (i) nerve fibre, types, identifiable on the basis of their content of granules and vesicles; (ii) the capillary arrangement; the development of the perivascular space and the relationships between nerve terminals and capillaries. In Hydromantes the neurohypophysial vessels, which may contain pericytes and nerve fibres, remai...
SUMMARY Historadiography was used to study tyrosinase activity in melanophores and the possible influence of MSH. 2G14-tyrosine was injected into Xenopus laevis larvae, under both normal and experimental conditions (namely, larvae with hypertrophy of the pituitary intermediate lobe and treated with methylthiouracil, and larvae treated with thiouracil only). A scanty tracer uptake was seen to occur in all animal groups. FISZPATRICK & KUKITA'S method for tyrosinase detection revelead that: 1. 2C14-tyrosine is incorporated into the melanophores of normal larvae at all developmental stages examined (stages 50–54); 2. there is a higher 2C14-tyrosine uptake by melanophores of larvae treated with thiouracil only, compared with those of operated and thiouraciltreated larvae. Biochemical investigations revealed an overall increase in melanin amount in the larvae with a hypertrophic pituitary intermediate lobe with respect to normal larvae. These results are briefly discussed.
SUMMARY 1. Support is cited for the establishment of a separate family, Chacidae comprising the monotypic genus Chaca based on the obtained osteological data. 2. The osteological characterisation of family Chacidae as well as genus Chaca is provided: very broad and depressed skull; very wide mouth gape bounded by unequal jaws; quite broad ethmoid with long and stout cornua; strongly projecting lateral ethmoid; toothless but conspicuous vomer; forked lachrymal; suborbitals lacking; very much reduced nasals; occipital process peculiarly modified. Movable premaxillae, quite large and broad palatine; minute ectopterygoid; hyomandibula solely sustained from the sphenotic; single hypohyal; eight branchiostegal rays; no basibranchials and gill-rakers and single pharyngobranchial. 3. The relationship of the family Chacidae with the Siluridae, Plotosidae, Bagridae and Sisoridae on the evidence of osteology is discussed and osteological support is found for its close affinity with the Sisoridae. 4. A brief discussi...
SUMMARY In Bufo bufo larvae the action of STH and LTH on body weight, processes of metamorphosis, and the cytologic pattern of the hypophysis and thyroid glands were studied. Furthemore, biochemical investigations were carried on the liver glycogen content and some enzymes involved in its synthesis and breakdown. Generally, STH-treated larvae underwent a loss in body weight, which might be related to the acceleration of metamorphosis shown by them as compared to controls. A pattern of definite hyperfunction is exhibited by the thyroid; in the adenohypophysis thyrotrophs result much degranulated. A decrease in the liver glycogen content and a decline in the activity of glycogen-synthetase was caused by STH, while phosphorylase activity was unchanged. In LTH-treated larvae, a statistically significant increase in body weight higher than in controls was seen to occur. The unfolding of metamorphosis in the early stages, at least, resulted wholly similar to that of controls, although in the treated larvae a mo...
SUMMARY The effects of ovine FSH (NIH-FSH-S9) and LH (NIH-LH-S18) on spermatogenesis was studied in Triturus cristatus carnifex Laur. The following responses were obtained: 1. In intact adult male newts, reared under winter-like temperature conditions (10°C), treatment with a combination of LH and FSH for 30 days brought about spermiation and a recrudescence of spermatogenesis up to the formation of large amounts of leptotene spermatocytes. Subsequent treatment for 20 days with LH or FSH given separately, or again in combination, elicited further progress of spermatogenesis up to the pachytene stage. Occasionally, metaphase I, though anomalous was attained. 2. Treatment of hypophysectomized specimens with FSH + LH at room temperature (about 18°C) in spring promoted testis maturation up to the pachytene stage. In one individual spermatogenesis progressed up to round spermatids. 3. Full spermatogenesis was achieved in the testis from hypophysectomized individuals given FSH + LH in the month of July (22–23°C...
SUMMARY Adult specimens of the hermaphrodite synchronous teleost, Serranus scriba were treated with methyl-thiouracil in order to identify the TSH secreting cells in the adenohypophysis. The thyroid of treated animals becames goitrous with hypertrophy of the follicles, which became lined with columnar epithelium. In the adenohypophysis the PAS and TP cells of the rostro-ventral cords accumulated their secretion. The basophils of peripheral cords of the gland and those distributed along the ramification of the neurohypophysis in the adenohypophysis were not affected by this treatment. Morphological changes of the thyroid gland during reproduction were also studied when an increase in the number of thyroid follicles was observed. During this period they were lined with a columnar epithelium. These changes are in correlation with the number of basophil cells of the adenohypophysis.
SUMMARY Little was known of the internal structure of a pair of enigmatic organs, the pseudoculi or post-antennal organs, situated dorso-laterally on the head of Acerentomids Protura. Externally the pseudoculus appears as a slightly convex elliptical disc with a longitudinal median depression. In transverse sections the organ presents a cavity bounded externally by an exocuticular cap and internally by a plate consisting of exo and endocuticle. Pore-canals are present in the cap. An oblique canal crosses the median posterior part of the organ floor. Ciliary extensions of six sensory neurons and processes of some epidermal cells penetrate into the cavity through this opening. The characteristic fine structure of the pseudoculus excludes its being an eye or a rudimentary antenna while the presence of ciliary processes and pore-canals lead to the conclusion that it is a sense organ with a chemosensory function. Differences between it and other Insect sense organs and probable homologies with the Collembola p...
SUMMARY A second specimen of Agamodon anguliceps immaculatus Calabresi, 1927 (Reptilia Amphisbaenia) provides proof of the validity of this taxon.
SUMMARY It has been suggested by many authors that in Cardium edule populations the number of ribs varies with changing salinity values. Observations collected from a population living in the « Valle di Comacchio » show a correlated change in the number of ribs and the length of the shell when measured in dead cockles while no such correlation is detectable in living specimens. Research, performed on a laboratory strain of Drosophila has enabled us to collect information about the effect of directional selection on the correlation between morphological traits which presents analogies with the observations made on Cardium edule in the wild. The results obtained suggest that the correlation between traits is disrupted only when, at a given moment in the selection process, the directional selection pressure is relaxed. It is therefore suggested that in Cardium edule the disruption of the correlation between the number of ribs and the length of the shell should be attributed to the relaxation of a selection p...
SUMMARY 1. Support is cited for the establishment of a separate family, Chacidae comprising the monotypic genus Chaca based on the obtained osteological data. 2. The osteological characterisation of family Chacidae as well as genus Chaca is provided: very broad and depressed skull; very wide mouth gape bounded by unequal jaws; quite broad ethmoid with long and stout cornua; strongly projecting lateral ethmoid; toothless but conspicuous vomer; forked lachrymal; suborbitals lacking; very much reduced nasals; occipital process peculiarly modified. Movable premaxillae, quite large and broad palatine; minute ectopterygoid; hyomandibula solely sustained from the sphenotic; single hypohyal; eight branchiostegal rays; no basibranchials and gill-rakers and single pharyngobranchial. 3. The relationship of the family Chacidae with the Siluridae, Plotosidae, Bagridae and Sisoridae on the evidence of osteology is discussed and osteological support is found for its close affinity with the Sisoridae. 4. A brief discussi...
SUMMARY Experiments were made on a population of Talorchestia martensii Weber from the sandy beach of Gesira, located 10 km S of Mogadiscio (STFD = 132°; LTFD = 312°) with the aim of controlling whether these Amphipods are capable of a directional orientation in experimental conditions of complete darkness and aridity. These experiments were made with adults collected a few days or immediately before each test as well as with young born and raised in the laboratory. The tests were made in the spring of 1969 in the phase of positive solar declination, both 60 km inland and on the home beach, at various hours during the day. Although of the test conditions were definitely motivating for the animals, no evidence was obtained to support the view that the population studied is capable of correct orientation towards sea or land when visual cues are excluded.
RESUME Apres un examen rapide des principaux types de concepts de genre en zoologie, nous proposons de considerer les genres comme des unites evolutives, c'est-a-dire des unites a la fois phylogenetiques, genetiques et ecologiques. Unites phylogenetiques: les genres doivent etre des taxons monophyletiques au sens de Ashlock {1971), c'est-a-dire holophyletiques ou paraphyletiques mais non polyphyletiques. Unites genetiques: les genres doivent regrouper des especes ayant une grande similarite genetique; parmi plusieurs methodes envisageables pour mesurer celle-d, attention est attiree sur l'interet de l'etude de l'hybridation interspecifique, et il est notamment suggere que lorsque deux especes peuvent donner naissance entre elles a des hybrides adultes viables, ces deux especes doivent etre incluses dans le meme genre, et de plus que si ces deux especes etaient auparavant classees dans des genres distincts, ceux-ci doivent etre reunis. Unites ecologiques: les genres doivent etre concus comme des ensembles ...
SUMMARY Machilis distincta Janetsch spermatozoon has been studied by both the transmission and scanning electron microscopes. This spermatozoon, otherwise normal in the sequence of its various portions, is endowed with some peculiarities, the most striking of these being its bending on itself head-to-tail at maturity. Owing to the fact that both halves are invested by a common membrane, the wrong impression is gained that the functional unit consists of a pair of spermatozoa. The accessory fibres, compressed by two conspicuous lateral structures are confined to either side of the flagellum. When the spermatozoa reach the spermatheca the accessory fibres are seen to be packed together by a material which is glycoprotein in nature. In the mature sperm both the acrosome and nucleus appear helically coiled and encircled by a sleeve of microtubules.
Click to increase image sizeClick to decrease image size RIASSUNTO L'Autore ha studiato una collezione di Lamiinae (Coleoptera Cerambycidae) raccolti durante cinque missioni del Centro di Studio per la Faunistica ed Ecologia Tropicali del C.N.R., per lo studio ecologico della spiaggia e della duna di Sar Uanle (Somalia meridionale, 0°29′48''S-42°25′ 30''E). Tra il materiale studiato risultano tre specie nuove per la scienza: Eunidia somalica n. sp., Oberea postbrunea n. sp. e Phytoecia fuscolateralis n. sp. SUMMARY A study of the Lamiinae (Coleoptera Cerambycidae) collected during the course of ecological research on the beach and dune at Sar Uanle (southern Somalia, 0°29′48''S-42°25′30''E), conducted by the Centro di Studio per la Faunistica ed Ecologia Tropicali of the Consiglio Nazionale delle Ricerche revealed the presence of three new species: Eunidia somalica n. sp., Oberea postbrunea n. sp. and Phytoecia fuscolateralis n. sp.
SUMMARY New experiments have been made on homing pigeons deprived of olfactory perception by occlusion of both nostrils with cotton tampons, or by resection of the olfactory nerve on one side and occlusion of the nostril on the other. They confirm the strong disturbance of orientation of the birds at the moment of release, which had already been observed in subjects with both olfactory nerves resected. Observations conducted on subjects with resected nerves have not shown other disturbances in general behaviour. The possibility is considered that, at the home site, pigeons associate odorous stimuli carried by winds from the surroundings with the direction from which they come. Recognizing a known odour at the release point, they should thereby be able to orient themselves toward home by flying in a direction opposite to the one with which the odour had been associated.
SUMMARY Using the scanning electron microscope the Author has studied the cuticle of some specie of the tribe Sminthurini. The results confirm, for the genera examined, the systematic position established by RICHARDS. Moreover the Author describes the new genus Caprainea n.g. on the basis of the characteristics of Caprainea echinata (Stach) (= Sminthurus echinatus Stach).
The spermatozoon of Macrobiotus hufelandii Schultze is composed of three regions: (i) a cylindrical acrosome showing a halo of electron dense material and a more transparent core with slender fibre...
High voltage electron microscopy in thick sections as well as in thick serial sections has made it possible to observe more detailed structure of the cilia of Urostyla cristata Jerka-Dziadosz than ...
Testes of the Japanese freshwater turtle Clemmys japonica Temminck & Schlegel were fixed using a triple fixation procedure. Intranuclear tubular structures, approximately 800 A in diameter, were ob...
