摘要:

AbstractAnalyses of the fine structure of the posterior choroid plexus in the teleostLeuciscus rutilusand the determination of the presence and function of the enzymes acid and alkaline phosphatases, ATPase and glucose‐6‐phosphatase confirm similarities between these epithelial cells and thesaccus dorsalisand also with the epithelial cells of the choroid plexus found in mammals. The teleost plexus cells contain coated vesicles which are derived from the plasmalemma as well as from the Golgi complex. Moreover, they contain multivesicular bodies and Iysosomes. These organelles function in the absorption of substances from the cerebrospinal fluid and in the breakdown of these substances within the cells. The investigated enzymes play an important role in the secretion of electrolytes into the cerebrospinal fluid by active membrane transp

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1973.tb00437.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract1Following transfer to sea water, the juxtaglomerular cells ofTilapia mossambicaincrease in number and size, reaching a maximum at 12 days, and returning to the original condition by 30 days.2A possible role for renin in osmotic adaptation of teleost fish is suggested.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1973.tb00438.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract1Urotensin II (bladder‐contracting activity) is present in the caudal spinal cords of teleosts, elasmobranchs, holosteans, and chondrosteans, in order of decreasing activity. It is questionably present in holocephalans and probably absent from lungfishes.2Cyclostomes and tailed amphibians show no evidence for any specific caudal urotensin II.3The pharmacological evidence parallels the cytological evidence for the occurrence of a caudal neurosecretory syste

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1973.tb00439.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractSiren intermediais peculiar in that the lateral‐line system is retained throughout life, even though the animal is forced into terrestrial situations during aestivation. The lateral‐line system is constructed of neuromasts arranged in pit fields instead of pit lines as in most amphibians. The neuromasts are unusual, because the sense cells are arranged in a single row through the long axis of the organ and a few of the sustentacular cells contain “orange granules.”During aestivation, the neuromasts are either shielded by a secreted cocoon, or occluded by proliferated skin epithelium. Those organs occluded by epithelium undergo dedifferentiation which continues through postaestivation.Loss of the lateral‐line system by amphibians was apparently late in amphibian evolution. Gradual loss of the system suggests that retention and/or protection of the lateral‐line system proved maladaptive and physiologically too expensive. Thus the system was abandoned by most amphibian taxa at me

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1973.tb00440.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractThe spermatozoa ofPetrobiusandLepismashare a few general insect features (filamentous shape, two mitochondria, compact acrosome vesicle, bilateral symmetry) but differ fundamentally with regard to specializations. InPetrobius, a long coiled acrosome, a coiled nucleus, and a “body” with axonema, two mitochondria, and a pair of lateral bodies follow each other in normal sequence. InLepismathe acrosome is a small vestige in the spoon‐shaped anterior end, the centriole is dislocated anteriorly, and nucleus, two mitochondria and axonema run like parallel filaments through most of the spermatozoon. The centriole adjunct develops into a postnuclear body inLepismabut forms a pair of complicated “lateral bodies” inPetrobius.It is concluded that ancestral forms must have had fairly primitive spermatozoa and that specialization has proceeded independently within each evolutio

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1973.tb00441.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractThe Brain of the Rainbow Trout (Salmo gairdneri, Pisces, Teleostei, Salmonidae). Looking for a reference size for quantitative studiesThe variability of the brain‐weight in the rainbow trout (Salmo gairdneri) is less than that of the body‐weight. The variability of the lengths studied (standard, total, preanal and cephalic lengths) is comparable and approaches that of the body‐weight's cubic root.The intraspecific brain/body‐weight relationship shows an allometric coefficient of .472, a little more than in Reptilia (Saurians: .39) and much more than in Mammalia (.23).The study of the various relationships brain‐weight/lengths and lengths/body‐weight shows that the preanal length is the best, and the cephalic length the worst in each case. It is therefore possible to substitute for the body‐weight this preanal length, the variation of which following most closely, in our instantaneous sample, both body‐ and brain‐weight's variations.ZusammenfassungDas Gehirn der Regenbogenforelle (Salmo gairdneri, Pisces, Teleostei, Salmonidae). Untersuchung einer Bezugsgrösse für quantitative StudienBei der Regenbogenforelle (Salmo gairdneriRichardson) ist die Variabilität des Hirngewichts deutlich geringer als die des Körpergewichts. Die Variabilität verschiedener untersuchter Liniarmasse (Standardlänge, Totallänge, Preanallänge und Kopflänge) ist vergleichbar und ähnlich jener der Kubikwurzel aus dem Körpergewicht.Die innerartliche Hirn‐Körpergewichtsbeziehung folgt beiSalmo gairdnerieinem Allometriekoeffizienten (Regressionskoeffizienten) von 0,462, d.h. ist merklich grösser als bei den Eidechsen (0,39) und den Säugern (0,23).Das Studium der Beziehungen zwischen dem Hirngewicht und den verschiedenen vorgenommenen Längenmessungen und der letzteren mit dem Körpergewicht zeigt, dass die Korrelationen mit der Praeanallänge (a) am besten, die mit der Kopflänge (c) am schlechtesten sind.Man kann deswegen das Körpergewicht durch diese Praeanallänge ersetzen, deren Variation denen des Gehirns und Körpers am besten korreliert ist.RésuméChez la Truite Arc‐en‐ciel (Salmo gairdneriRichardson), la variabilité du poids encéphalique est bien plus faible que celle du poids somatique. La variabilité des diverses mesures linéaires testées (longueurs standard, totale, préanale et céphalique) est comparable et voisine de celle de la racine cubique du poids somatique.La relation pondérale encéphalo‐somatique intraspécifique a pour coefficient d'allométrie 0,462 (coefficient de régression) chezSalmo gairdneri, c'est à dire sensiblement plus que chez les Reptiles Sauriens (0,39) ou les Mammifères (0,23).L'étude des relations liant le poids encéphalique aux diverses mensurations effectuées et ces dernières au poids somatique indique que c'est la longueur préanale (a) qui est la meilleure et la longueur céphalique (c) la plus mauvaise. On peut donc substituer au poids somatique cette distance préanale, dont les variations suivent au plus près, pour un échantillon instanta

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1973.tb00442.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractIn some planulae of the alcyonarianGersemia rubiformisan interior structure was found in the entodermal cavity. It consisted of two layers separated by a basement membrane, the inner layer facing a central cavity. The outer layer was structurally identical with the inner “entomesoderm” of the body wall, while the inner layer of the “ball” was provided with numerous cilia and a brushborder. The development of the interior structure is described as appearing from the structural findings in different planulae. This development is very different from any other developmental process described

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1973.tb00443.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractDesert locustcorpora cardiacahave been treated with hydrolytic enzymes in saline solution in order to facilitate separation of individual intrinsic cells. Some of the enzymes digested the basal lamina covering thecorpus cardiacum, and also the intercellular cementing substance. Living neurosecretory cells with axonal projections could be isolated and observed by phase contrast microscopy or by darkfield illumination. By morphological criteria the secretory cells should be characterized as neurons, and two different types of secretory neurons have been identified. Brownian movement of cytoplasmic particles occurs in damaged cells and is regarded as a post mortem phenomenon.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1973.tb00444.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY