摘要:

AbstractTwo kinds of cilia have been observed in the pharynx ofGlossobalanus minutusKowalewsky. From the present study, a ciliary specialization can be found in order to move a determinate substance, i.e. mucus or water. Mucus‐moving cilia (type I cilia) have a single basal centriole and poorly developed ciliary rootlets. Their tips are rounded, bearing an inner, asymmetrical cap attached to some tubules. Water‐moving cilia (type II cilia) are exclusively located at lateral epithelia of branchial bars, giving rise to the water current through the gills. They have two basal centrioles, proximal and distal, and a complex system of ciliary rootlets made up of a principal rootlet, a secondary or accessory rootlet and a ‘fan’ rootlet. The tips of type II cilia have a long process with some tubules inside. All basal structures are precisely orientated in order to assure a good coordination of ciliary beat. The possible functional significance of ciliary substructure is also discussed. From these observations a model for mucus and water currents through gill slits is pos

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1988.tb00895.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe ultrastructure of the connective tissue spaces in the clitellar epithelium has been studied in the earthwormLumbricus friendi.Four morphological types of coelomic cells are described: amoebocytes, mucocyte‐like cells, pigment cells and crystal‐containing cells. The amoebocytes are characterized by the presence of spherical to oval electron‐dense granules, phagocytic vacuoles and numerous microtubules located in the Golgi areas. The mucocyte‐like cells show the features of the mucocytes reported in enchytraeid worms (globular inclusions with filamentous and homogeneous, moderately electron‐dense material, as well as a filopodous process). The pigment cells contain typical spindle‐shaped osmiophilic granules, microtubules (not reported before) and glycogen particles. The crystal‐containing cells show inclusions which are polygonal in section with a striated substructure (periodicity of about 4.5 nm). Apart from the mucocyte‐like cells, the coelomocytes showed cytoplasmic processes attached to the basement membrane of the spaces. The possible functions of these cells are discussed and a common peritoneal origin is postulated on the base of their morphological and cytol

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1988.tb00896.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe cavernous body of the ammocoetes of the anadromous sea lampreyPetromyzon marinuswas ultrastructurally analyzed with special emphasis on its lymphoid components. It is a vascular structure differentiated from the afferent artery of each gill filament and contains a specialized phagocytic endothelial cell, named the cavernous body (CB) cell. In the vascular spaces of the cavernous body there occur numerous lymphoid cells, including lymphocytes, lymphoblasts, mature and developing plasma cells and large macrophages, which make contact with the CB cells. The role of these cells is discussed as to the suggested functions of the cavernous body in the defence mechanisms of lampreys.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1988.tb00897.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractImmunoreactions (IR) in the nervous systems (NS) of species representing the platyhelminthic taxa Acoela, Proseriata, Tricladida and Rhabdocoela (Dalyellioida, Typhloplanoida, Kalyptorynchia) have been studied by means of the peroxidase‐antiperoxidase (PAP) immunocytochemical method and the whole mount immunofluorescence (FITC) method. Antisera to the molluscan cardioactive neuropeptide FMRF‐amide, to the bioamine 5‐HT and to the vertebrate neuropeptides bovine pancreatic peptide (BPP), leu‐enkephalin, substance P and human growth hormone releasing factor (GRF) were used. Perikarya and fibres positive to FMRF‐amide antiserum (anti‐FMRF‐amide) appear in the NS of all investigated species. Since IR to anti‐FMRF‐amide has been obtained in worms representing taxa of all flatworm classes it is suggested that substances with similar sequences have been inherited from the stem form of Platyhelminthes. IR to 5‐HT antiserum (anti‐5‐HT) observed in the NS of all the investigated flatworms confirm the importance of this bioamine, which may have appeared early in platyhelminth evolution. IR to GRF antiserum was found in the acoel, the triclad and the rhabdocoel species, IR to leu‐enkephalin antiserum in the triclad and rhabdocoel species and IR to substance P ant

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1988.tb00898.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractTwo types of refractile inclusions in the integument of nemertean worms have been studied by X‐ray microanalysis and electron microscopy. The body wall ofTetrastemma bilineatumcontains ovoid concretions that are 10–20 μm long. Qualitative X‐ray microanalyses indicate that the concretions are composed of calcium, phosphorus, barium and perhaps magnesium and sodium. InZygonemertessp. andZ. virescensminute hook‐like structures occur throughout the epidermis. The hooks develop by one week post‐fertilization and appear to be non‐calcified in both larvae and adults. Each hook is formed within a large vacuole and consists of several fused subunits. The subunits lack well defined cortical and medullary regions and seem to be produced by the rough endoplasmic reticulum of the epidermal secretory cell. The possible relationships between the calcareous concretions and proboscidial stylets of nemerteans are discussed and the structure of the integumentary hooks is compared to that of rhabdite‐like bodies secreted by other

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1988.tb00899.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractAnatomically the brachiopterygian organum olfactus is unique among craniates. As revealed by the present study ofPolypterus senegalus, it consists of an incurrent and an excurrent tube, a body and six lobes. Luminally these divisions are extensively covered with cilia, the actions of which cause water to flow through the organ. The proximal extremities of the two tubes communicate directly with one another, allowing water to bypass the body and the lobes. The body is subdivided by means of seven infolds into a central part and two peripheral parts. Of these, the central part directs water to the lobes; the peripheral parts drain the lobes and lead water to the excurrent tube. Each lobe has an axial portion and two rows of alternating lobuli. Interlobularly infolds of the axial portion subdivide the lobar lumen in such a way that movement of water is possible. Olfactory neurosensory cells occur in the rear of the incurrent tube, as well as in the lobes. Probably the degree of stimulation of the tubal receptors determines whether the water taken in is to bypass the lobes.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1988.tb00900.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe entire nervous system of the smallest annelid hitherto known, the dwarf male of the highly dimorphic speciesDinophilus gyrociliatus, has been reconstructed by means of TEM investigations of serial ultrathin sections. Altogether there are 68 neurons, 40 of which have a sensory function. The structure and distribution of them is described. The receptor endings of the 20 sensory cells of each side are located either in two groups — the anterior receptor group and the posterior receptor group — or are singly positioned in the integument. Structural differences of the apical portion of the dendrites enables four types of receptors to be distinguished: three types with emergent cilia and one type with non‐emergent cilia. Neurons with emergent cilia can be monociliated collar cells as well as mono‐ or multiciliated cells without collar. Special vesicle‐in‐vesicle structures, are located close to the basal portion of the cilia in some of these cells. The non‐emergent cilia border closely to a neighbouring epidermal cell and contain a prominent intraciliary vesicle. The function of receptors is discussed with regard to a comparison with receptors in other polychaete species, structural specializations and their distribution pattern on the ani

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1988.tb00901.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY