摘要:

AbstractThe inner ear ofIchthyophis glutinosusis described with emphasis on the position of the sensory organs and the polarization of the hair cells. The hair cell polarization patterns of the maculae, cristae and papilla basilaris is similar to previous observations in other tetrapods. The papilla amphibiorum shows a simpler bidirectional polarization than described in other amphibians. The papilla neglecta, a sensory organ in the utriculus shows a unidirectional posteriorly directed polarization. A neglecta has not been found in the utriculus of anurans and urodeles previously.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1982.tb00751.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractIn a calving area on western Hardangervidda, Norway, shed antlers of female reindeer,Rangifer tarandus tarandusL., have been collected for several years. Many of these antlers have been chewed on by reindeer. In the literature antler chewing has been reported to take place on both shed and unshed antlers. Our observations support these findings. Based on the present observations it is suggested that the antlers may subserve the mineral householding of the animals under special conditions. The female reindeer has to pass through a nutritionally marginal season which often coincides with calving. Bringing the bony antlers to the calving areas seems advantageous in the maintenance of calcium balance. The growth of antlers may therefore be looked upon as part of a mineral saving strategy. The mineral stored in the antler thus represents a reserve to be used during pregnancy and lactation. This is in contrast to the common view that shedding of antlers is just waste of mineral when there is a great need for calcium.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1982.tb00752.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe present work analyzes by light microscopy circulating blood cells and lymphoid organs of the caecilian,ichthyophis kohtaoensis.Peripheral blood contains erythrocytes, thrombocytes, lymphocytes, monocytes, heterophils, easinophils and basophils. Thymus, liver and spleen are the major lymphomyeloid organs in this caecilian and there is not a haemopoietic functioning bone marrow. The results are discussed on the basis of the possible phylogenetic positions of the Apoda emphasizing their relationships to the Urodela.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1982.tb00753.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe transport speed of latex spheres trapped in the mucous feeding filter of 30 specimens ofCalvelina lepadiformis(Müller 1776) was measured by microscopical examination and a stop watch. The speed across the gill screen increased from 24 μm s−1in small animals to 220 μm s−1in large ones. The net translocation speed of the food roll behind the dorsal Lamina was generally much slower but revealed a similar trend (7–78 μm s−1). The increased feeding filter speed in larger animals was parallelled by an increased branchial circumference in such a way that the duration of water filtration through each part of the filter remained almost constant (between 38 and 56 s as means for all groups of animals). The amount of filter secreted by large animals approached 150 cm2h−1or 2.5 m2week−1. Based on available data on water filtration rates it could be calculated that the speed of water through the filter was of the same order of magnitude as the observed translocation spee

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1982.tb00754.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractTwo principally different wall types occur in the bryozoan colony:Exterior wallsdelimiting the super‐individual, the colony, against its surroundings andinterior wallsdividing the body cavity of the colony thus defined into units which develop into sub‐individuals, the zooids. In the gymnolaemate bryozoans generally, whether uniserial or multiserial, the longitudinal zooid walls are exterior, the transverse (proximal and distal) zooid walls interior ones. The radiating zooid rows grow apically to form “tubes” each surrounded by exterior walls but subdivided by interior (transverse) walls. The stenolaemate bryozoans show a contrasting mode of growth in which the colony swells in the distal direction to form one confluent cavity surrounded by an exterior wall but internally subdivided into zooids by interior walls. In the otherwise typical gymnolaemateParasmittina trispinosathe growing edge is composed of a series of “giant buds” each surrounded by exterior walls on its lateral, frontal, basal and distal sides and forming an undifferentiated chamber usually 2–3 times as broad and 3 or more times as long as the final zooid. Its lumen is subdivided by interior walls into zooids 2–3, occasionally 4, in breadth. This type of zooid formation is therefore similar to the “common bud” or, better‐named, “multizooidal budding” characteristic of the stenoleamates but has certainly evolved independently as a special modification of the u

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1982.tb00755.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractWe have studied the ultrastructure of the testis and interstitial tissue of lizardLacerta muralissacrificed in spring, summer and autumn, with special emphasis on the morphological changes of Leydig cells. From the autumn to the end of spring, Leydig cells showed a large smooth endoplasmic reticulum and mitochondria with tubular cristae. These features correlate with the synthesis and secretion of androgens. At the end of spring and after mating, the amount of smooth endoplasmic reticulum decreased and the mitochondria showed laminar cristae. Both features are typical of a latent period, during which time secretion of androgens remains inactive until the end of summer. The possible role of other cell organelles, such as Golgi complex and lysosome‐like electron dense bodies, during both secreting and resting periods, is also discussed. Finally, we consider the relationship between seasons, secretory activity of Leydig cells and the spermatogenic cycl

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1982.tb00756.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractCorpuscles of de Quatrefages in the rostral connective tissue of amphioxus have been serially sectioned and examined in the electron microscope. It is shown that each corpuscle is composed of one or a few main cells separated and enveloped by sheath cells. From the main cell two cilia protrude into a lumen formed by a bulge in the sheath. The ciliation of the main cell and its axonic continuation into one of the associated nerves suggests that this cell is a primary sensory neurone and the corpuscles of de Quatrefages probably mechanoreceptors.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1982.tb00757.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractSpecific, fluorescent, subependymal perikarya were found in thepars anteriorof the paraventricular organ (PVOpa), in thenucleus recessus lateralis(NRL) and in thenucleus recessus posterioris(NRP). No fluorescent perikarya were present in thenucleus lateralis tuberis(NLT). Fluorescent nerve tracts connect the PVOpa and the NRL with the NRP, and interconnect the paired NRP. Thenucleus preopticus(NPO) and the NLT receive a large input of aminergic nerve fibers. The monoaminergic nuclei are well vascularized, and their vascular plexes seem to be connected. A capillary plexus is situated dorsal to the NRP and exhibits no contact with the pituitary. It is surrounded by the prominent fluorescent tracts connecting the aminergic nuclei.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1982.tb00758.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThis study examines the effect of food deprivation, increased ambient salinity and prolactin administration on the thyroidal response to ovine TSH, andin vitrohepatic monodeiodination of T4 to T3 in coho salmon,Oncorhynchus kisutch.Fed fish and fish food‐deprived for 18 days showed similar significant increases in plasma T4 9 and 24 h after a single injection of TSH. Plasma T3 levels were also elevated in both fed and food‐deprived fish 9 h after the TSH injection but plasma T3 levels in the food‐deprived fish were markedly lower than in the fed salmon. The increase in T4 and T3 evident in freshwater‐acclimated fish after TSH administration was not found in salmon acclimated to 65% sea water. Prolactin, given alone (either as a single injection or a series of three daily injections) had no effect on plasma T4 or T3 levels. When given together with TSH prolactin prolonged the T4 and T3 elevating effect of TSH. Food‐deprived salmon had lowerin vitrohepatic T4 to T3 conversion rates than fed groups but T4 to T3 conversion did not appear to be affected by increased ambient salinity, or by prolactin and/or TSH admin

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1982.tb00759.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY