摘要:

AbstractMales ofUlomyia fuliginosapossess two pairs of eversible mesothoracic appendages. A detailed investigation of the anterior appendages, especially of the hypertrophied cup‐shaped cells, every one which is covered by a cuticular knob, is presented in this paper. The most striking feature of these cells is the apical plasma membrane, which is deeply invaginated into the cell, intensively folded and surrounded by cytoplasmic zone tightly packed with mitochondria. The intracellular equipment with organelles resembles that of pheromonesecreting cells of insects. Morphological evidence of neurosecretornotor control of the cells' activity is given.—Females are not prepared to copulate when the anterior mesothoracic appendages have been put out of use. As a result of the findings in this study the cup‐shaped cells are presumed to be concerned with the secretion of an aphrodisiac subs

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1981.tb00612.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe fine structure of the digitiform sensilla on the distal segment of the maxillar palps of Tenebrio and Dermestes is described. Each sensillum is associated with a single sensory cell and three enveloping cells, which enclose two receptor lymph cavities. The inner receptor lymph cavity of both species shows a different structural feature. Branches of the outer dendritic segments, which contain numerous microtubules, run to the tip of the hairshaft. A dendritic sheath extends to the apex of the peg. The hairshaft possesses a second canal, which is free of dendrites. The poreless hairshaft is inserted in a cuticular canal; the longer distal part of the shaft is positioned in a narrow superficial groove.The digitiform sensilla do not show the typical structures of mechanosensitive sensilla. The absence of pores in the setal wall does not point to a function as olfactory or gustatory hairs. The presumed function of the sensilla is discussed in relation to thermo‐, hygro‐ and CO2‐rece

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1981.tb00613.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe sense organs of the marine arthrotardigradesHalechiniscus greveniRenaud‐Mornant&Deroux andBatillipes noerrevangiKristensen were investigated with the aid of interference phase‐contrast and transmission electron microscopy. The sense organs of the two species are quite different in outer cuticular morphology, but the inner cellular parts are constructed after the same model: the arthropod sensory setae. All investigated sensilla contained ciliary structures. Regeneration of the cirri during moult is very similar to the regeneration process in insects and spiders, but in the two arthrotardigrades the trichogen cell is not retracted from the cuticular part of the setae after moult. The clava is presumed to be olfactory; the cephalic cirri and the leg spines are contact chemoreceptors with one mechanoreceptive cilium terminating at the sensillum shaft. Cirrus E is compared with the trichobothrium of arthropods and the phylogenetic implications of the investigated structures are discus

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1981.tb00614.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe thyrotropin (TSH) producing cells are distributed in the rostral and proximal pars distalis. This cell type is the smallest and most infrequent cell of the adenohypophysis. Its cytology is similar to the smallest gonadotropic (GTH) cells although the two cell types can be separated by the size of the small secretory granules (diameter less than 200 nm) in the TSH cells. In presmolts and smolts the cells are morenumerousthan in parr and adult salmon and have cytological features indicating an increased activity. This was also the case after intraperitoneal injections of synthetic TRH. Antisera to carp GTH and salmon GTH cross‐reacted with both the GTH and the TSH cells. Anti‐human TSH cross‐reacted only with the TSH cells which confirms the assumption of antigenic similarity between human and fis

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1981.tb00615.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractTransmission and scanning electron microscopy of food trapping filters or “mucous films” of several Ascidians reveal the same type of extensive net with elongate rectangular meshes. The ultrastructural appearance and mesh size varies only slightly within the group. Pore sizes from 0.2 to 0.5 μm in width and from 0.5 to 2.2 μm in length with a thickness of the filaments from 10 to 40 nm are probably representative for the nets underin vivoconditions. These observations corroborate earlier experimental results which indicate a remarkably high and constant efficiency of filtration in all species kept undisturbed.Great quantities of water are evidently filtered through these nets at relatively low resistance and particles even below bacterial size (0.5 μm) are effectively trapped. Histochemical reactions indicate the presence of both mucoproteins and acidic polysaccharide components and that the filaments are probably made up of a peptide core surrounded by polysacch

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1981.tb00616.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY