摘要:

AbstractThe Eyes of the Fossil Cyclostomes and the Problem of the Origin of MyxinoidsStudies on orbital cavities in various fossil Cyclostomes have yielded certain conclusions as concerns the organ of sight and the arrangement of the extrinsic ocular muscles in these ancient animals. Thus, evidence is offered that osteostracans possessed spheroidal eyeballs similar to those of present‐day petromyzontids; also, that heterostracans were equipped with conical eyeballs closely conforming to those encountered in the recent myxinoidEptatretus burgeri.On the basis of the last‐mentioned resemblance, the shape of the prenasal sinus, the construction of the biting mechanism, the lack of a pineal foramen, the presence of a common external aperture for the ipsilateral gill‐slits, and the probable existence of a paired longitudinal row of mucous glands, it is further suggested that heterostracans and myxinoids are immediately related.RésuméLa forme et la musculature des yeux des Cyclostomes fossiles peuvent être reconstituées à partir de l'étude de la cavité orbitaire. Il apparaît alors que l'organisation de l'ceil des Ostéostracés devait être très proche de celle de l'ceil des Pétromyzontides tandis que l'ceil cônique des Hétérostracés rappelle fortement celui du MyxinoïdeEptatretus burgeri.Ce caractère, joint à la structure du sinus prénasal, au type de mécanisme buccal, à l'absence de foramen pineal, à la présence d'un orifice branchial commun et à l'existence probable de rangées de glandes mucogénes, nous oblige à considérer les Hétérostracés comme les formes les plus proches des Myxinoïde

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1975.tb00077.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe brain ofNephtyscontains four neurosecretory cell types with distinctive cytoplasmic inclusions,acells are located uniquely in a single pair of ganglionic nuclei andbcells are represented by a single pair of cells, whereasccells anddcells have a scattered distribution. Their axons form two types of secretory release structure. First, possible axon collaterals synapse upon slender “dentritic twigs” in the core of the brain. Secondly, two tracts descend to the brain floor to form a “neurosecretory neuropile” (or storage and release complex) in contact with the inner surface of the brain capsule. Other neurosecretory fibres penetrate through the capsule, branch extensively, and terminate in contact with its ventral surface in close association with the “infracerebral gland”. The gland is derived from the pericapsular epithelium and exhibits signs of specialization for glandular function. In contrast to certain other polychaetes, it does not contain secretory neuron perikarya. The secretory end‐foot system is poorly developed. Its terminals are located adjacent to the neurosecretory neuropile, which they encircle. The cell bodies are probably represented by fourecells which, like the terminals, contain many

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1975.tb00078.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractProlactin (LTH) and growth hormone (GH) containing cells inA. güldenstaedtihave been localized by means of anti‐ovine prolactin and anti‐bovine growth hormone respectively, coupled indirectly to peroxidase, and localized histochemically with hydrogen peroxide as substrate and 3,3′‐diaminobenzidine as capturing agent.The distribution of the anti‐prolactin positive cells has been demonstrated and correlated histologically with the acidophilic cells both in the rostral and proximal pars distalis. This cell type is elongated and arranged in follicles in the rostral pars distalis; in the proximal pars distalis they are smaller and oval, without any special orientation.Neither of the other cell types which are scattered among these acidophils contain prolactin.The anti‐bovine growth hormone positive cells are evenly distributed in the proximal pars distalis above the hypophysial cleft, and some are also found in the pars intermedia. The anti‐GH positive cells have been correlated histologically with the amphiphilic cells in the proximal pars distalis. These cells are arranged in cell cords in close contact with the secondary capillary plexus, near its origin from the primary capillary plexus covering the m

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1975.tb00079.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractTwo endocrine cell types, PbH+ and PAS+ cells, were recognized in the pars intermedia (PI) of the roach,Leuciscus rutilus, by light and electron microscopy. They can be distinguished by the appearance of their secretory granules. The PAS+ cells stain with toluidine blue in semithin sections as opposed to the PbH+ cells.After 5 days' treatment with metopirone the PbH+ cells are highly activated whereas the PAS+ cells show no response. The PbH+ cells are assumed to produce MSH. In roaches adapted to diluted sea water (10%) the transfer to fresh water for 1—1 1/2 hours or reserpine injections for the same period had no notable effect on neither cell type.Three kinds of axons innervate the PI. Two of these, which have granules averaging 111 nm and 151 nm in diameter, originate in the nucleus preopticus (NPO). The third type of axons has granules of an average size of 74 nm and is probably aminergic.The glia cells in this part of the neurohypophysis (NH) are granular pituicytes, which are innervated by all three axon types.The border between the NH and the PI is composed of a double basement membrane from which a network extends into the NH. This network, the basement membrane and the capillaries are the main sites for the terminations of the axons although nerve fibers also invade the endocrine tissue. Only axon type 3 was observed to synapse frequently with the PbH+ cell

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1975.tb00080.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractIntraperitoneal injection of mammalian thyrotropin‐releasing hormone (TRH) caused hypertrophy of possible thyrotropic cells in the pituitary gland of the teleost,Chasmichthys dolichognathus.The epithelial cells of the thyroid follicles also appeared hypertrophic after the TRH injection. On the other hand, in the hagfish,Eptatretus burgeri, TRH injection had no effect either on the cytological appearance of the adenohypophysis or on the thyroidal activity in terms of serum thyroxine concentration and epithelial cell heigh

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1975.tb00081.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Abstract1The hypothalamo‐hypophysial neurosecretory system in the Red‐winged Blackbird (Agelaius phoeniceus) has been studied with special reference to changes during the period prior to fall migration.2In September the supraoptic and paraventricular cells were found to be considerably larger with substantial amounts of aldehyde fuchsin positive neurosecretory material (NSM) accumulating in the perikaryon. Large amounts of the NSM were found also in the anterior median eminence and pars nervosa.3Towards migration time (November), the cells in the hypothalamic nuclei contained very little NSM. A marked decline in the amount of NSM was also seen in the anterior median eminence and probably in the pars nervosa too.4The release of NSM toward migration time has been discussed as an important event in the sequence of events that control and regulate migratory activ

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1975.tb00082.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe ultrastructure of the bacterial symbiotes in the pharyngeal diverticula of adult olive flies [Dacus oleae(Gmelin)] was examined. The diverticulum was an extension of the foregut formed by a row of epithelial cells bounded by an inner layer of cuticle. Towards the hemolymph, the epithelial cells showed an infolding of their basement membrane while adjacent to the cuticular lining, the cells contained a zone of extensive membrane proliferation. The diverticula were packed with bacterial rods which possessed elongate filamentous and short catenulate appendages. The function of these appendages is unknown. They did not resemble fimbriae (pili), flagella or prosthecae described from other bacteria.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1975.tb00083.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractAn investigation has been made of the resistance time and upper lethal temperature of ammocoetes of four species of lampreys provided with a substrate into which they could readily burrow. In general, ammocoetes burrowed after transfer from the acclimation to the experimental temperature baths and later came out of the substrate only in lethal temperatures. A relationship was observed between the resistance time and the time taken to emerge, with the resistance time increasing exponentially with decreasing experimental temperature. InIchthyomyzon fossor, landlockedPetromyzon marinus, Lampetra (Lethenteron) Lamotteniiand inLampetra (Lampetra) planerifrom two different times of the year, the incipient lethal levels over a two week experimental period for larvae acclimated to 15° G were respectively 30.5, 30, 29.5, 28.5 and 28° C. Values forP. marinusacclimated to 5 and 25° C were respectively 29.5 and 31° C, whereas inL. planerithey were 28 and 29° C in April/May and 27 and 29° C in July/August. Extrapolation of the results for the three acclimation temperatures yielded ultimate incipient lethal levels of 31.4° G inP. marinusand 29.2 and 29.4° C forL. planeriexamined in the spring and summer respe

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1975.tb00084.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.tb00085.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY