摘要:

AbstractThe pro‐adenohypophysis (pro‐AH) of migrating adult river lamprey,Lampetra fluviatilis, has been examined from October, when the gonads are developing slowly, until May, when the sexual maturation is completed.Two granulated cell types are dominating. One is chromophobic (C2, 95 nm), the other is basophilic (B1‐B3) and probably gonadotropic. The mean diameter of the basophil secretory granules increases from 150 nm in October to 220 nm in April and May. The staining affinity of a rare, granulated cell type (D, 115 nm) has not been established. No acidophil cells are found in the pro‐AH. The ultrastructural characteristics of the lead hematoxylin positive cells found sometimes in paraffin sections are unknown. Non‐glandular stellate cells are common. They contain microfilaments, are probably contractile, and transform to phagocytes during the last months before spawning. This phagocytosis involves only the basophil cells. It is suggested that the stellate cells in this way destroy excess hormone.All cell types in the pituitary accumulate large irregular lipid droplets during the last month before spawning. These lipid droplets seem to be expelled from residual bodies as an end product of autolysis and pha

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1975.tb00086.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractNew findings on the functional anatomy of filter feeding have permitted some clarification of water flow through tadopoles. The dorsal velar apparatus projects downward from the roof of the buccopharynx and consists of three mucosal pads and three vanes on both sides of the midline. At least four functions may be ascribed to the dorsal velar apparatus. 1. Each pad and its complementary vane fit so flush into each of the three bilateral filter cavities that exhalent water must flow in thin sheets over the filter plates before its exit via the pharyngeal clefts. 2. Like hydrofoils, the vanes deflect water and prevent strong currents from disorganizing the mucous food cords. 3. When tadpoles cease water pumping, the plugging effect of the dorsal velar apparatus in the filter cavities helps to occlude the pharyngeal clefts. 4. Secretions of dorsal velar glands, especially on the surface of the velar pads, may assist the mucus of the ventral velum to entrap suspended food.Other findings concern the M3b muscle, which helps to elevate the buccopharyngeal floor during expiration; the lack of cilia, but presence of low glandular elevations on the ventral velum; the reduction of the exits from the pharyngeal clefts 2 and 3 into a single valvular exit controlled by the B2b and B2c muscles; and the probable absence of a mechanical feeding function for the oral tentacles.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1975.tb00087.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractA detailed study of the structure of the heart and the general disposition of the efferent (arterial) vessels and afferent (venous) vessels is presented. The vascular system ofP. hawaiensisis compared with that of other species of amphipods and the differences are pointed out. All the appendages except the pleopods receive their efferent vessels directly from the heart and not from the sternal sinus.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1975.tb00088.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe ommatidia of the compound eyes ofArtemia salinaL. are normally composed of four crystalline cone cells containing glycogen. The cells are enveloped by two so‐called “cellules épidermiques juxta‐cristallines”. There are also six pigmented retinula cells, all contributing to the rhabdom.A peculiar feature of theArtemiacrystalline cone cells is that their elongated parts, the so‐called cone cell roots, widen and flatten proximally, forming interdigitating “endfeet”. The basement membrane thus consists of a cellular portion combined with the basal lamina.The main mass of the rhabdom of theArtemiaeye is built up by five retinula cells, two contributing a smaller part. The microvilli are oriented in four directions, two being orthogonal. The sixth cell contributes on two small portions to the rhabdom in the distalmost and a more proximal position. The rest of it runs axon‐like outside the omnatidium. Where the sixth cell wedges in, the direction of the microvilli is changed and has no orthogonal pattern.Two rhabdom types of compound eyes are distinguished: the decapod or banded or layered rhabdom: and the anostracan rhabdom with contin

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1975.tb00089.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractA peculiar cell type is described from the sensory vesicle of the brain of the appendicularian tunicateOikopleura dioica.The cells carry globular, modified cilia and resemble in several other respects the coronet cells of Saccus vasculosus in many fishes. This finding, together with earlier reports of similar cells in the sensory vesicle of ascidian tadpoles, makes it probable that a primitive form of coronet cells is a regular constituent of the tunicate brain cavity. The existence of coronet cells in the tunicate line of evolution is of interest from a phylogenetical as well as functional point of view. The author proposes that the tunicate sensory vesicle corresponds to part of the craniate third ventricle and that the tunicate coronet cells are involved in the regulation of the ventricle fluid composition.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1975.tb00090.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1975.tb00091.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY