摘要:

AbstractAfter a preliminary descriptive study of the “skeletal growth marks” often used among snakes as an empirical age index, this paper deals with the first experimental results. (1) OnVipera aspisgrown from birth under controlled, constant conditions and hence of known age, the number of skeletal growth marks is closely related to animal size, but this size has no relationship with individual age. (2) OnVipera aspissubmitted to seasonal variations under experimental conditions and bone labelled with fluorochromes, the number of growth marks added to the skeleton during the experimental study (two years) seems to be in accordance with this duration. This would demonstrate, at least theoretically, a relationship between skeletal growth marks and individual age, as well as incidences of environment conditions. These results are discussed.RésuméAprés une étude préliminaire descriptive sur la structure des marques squelettiques de croissance qui, chez les serpents sont utilisées de façon empirique comme indicateur de l'âge, le présent travail fait état de premiers résultats expérimentaux. (1) Chez des Vipères aspic élevées depuis leur naissance dans des conditions constantes, contrôlées (il s'agit donc d'animaux d'âge connu), le nombre de marques squelettiques est étroitement liéà la taille des animaux, mais comme elle, n'a plus dans ces conditions expérimentales de rapport avec l'âge. (2) Chez des Vipères subissant leur cycle saisonnier sous conditions expérimentales et dont on marquein vivopar fluorochromes le tissu osseux, le nombre de marques squelettiques mis en place pendant la durée de l'expérience (2 ans) correspond sensiblement à cette durée. Ceci tend à confirmer, en théorie, la relation entre les marques squelettiques et l'âge individuel et son interaction avec les conditions d'environn

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1974.tb00817.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe muscle fibres of the marine invertebratePriapulus caudatus(Priapulida) are obliquely striated. Thin and thick filaments and characteristic dyad structures were recognized. The ultrastructural organization shows more resemblances with that of arthropod muscles than with that of annelids or molluscs. Pharmacological studies show that the muscles are provided with “primitive” C 16 type of acetylcholine receptors. Tubocurarine, succinylcholine and decamethonium do not block the effect of acetylcholine but potentiate this. This remarkable response may be due to inhibition of choline esterase. No distinct structural or functional differences were observed between somatic and visceral muscles, but the rectum showed evidence of the presence of unspecific amine receptors. The pharmacological responses resemble in the main those known from various simply organized invertebrate phyla. The priapulids, as suggested by Lang in 1953, may te survivors of a very ancient animal gr

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1974.tb00818.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractChordodasys antennatussp.n. is described from sublittoral sediments off the US Atlantic Coast. This species has been also studied by transmission electron microscopy. The new species is particularly characterized by extremely enlarged sensory processes which have a segmented appearance. The fine‐structure of the chordoid organ, characteristic of the genusChordodasys, has been studied in both known species of this genus. According to this investigation the chordoid organ consists of plate‐like muscle cells, surprisingly similar to the notochord ofAmphi‐oxus. Particular emphasis has been made in this study to elucidate the fine structure of the body cavity and the system of lateral and central chambers as described by Remane in 1936. The electron micrographs substantiate the fact that gastrotrichs exhibit an acoelomate construction of their body cavity. The systematic position of the new species and the genusChordodasysis discussed in the light of the new ultrastruc‐tural info

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1974.tb00819.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractPopulations of Dugesia in Israel have been classified on morphological and karyological criteria into 5 types. Two of these are morphologically similar to the Dugesia lugubris group (n = 4) but differ karyologically (Types 1 and 2: n=8), and three types are morphologically similar to theDugesia gonocephalagroup (n= 8) but two differ karyologically (Types 4 and 5:n= 9). The three ‘gonocephala’ types are distributed in three distinct areas of Israel with little overlap, while the two ‘lugubris’ types are found in springs of one of these areas, The Rift Valley, where special localised conditions prevail. Possible relationships between Types 3, 4 and 5 are discussed with particular reference to their karyotypes and the presence of supernumerary chromosomes in

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1974.tb00820.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThree new species ofDesmoscolex, found in samples from Yonge Reef, Lizard Island, Nymphe Island and between One Tree Isles and Wistari Reef are described:D. australienssp.n., characterized by the head‐shape with naked semi‐circular anterior part, by the jointed cephalic setae inserted close to the anterior extremity and by the shape of the gubernaculum with less sclerotized proximal part;D. membranosassp.n. close toD. granulatusDecraemer, 1974, but differing from it by the presence of a partly disconnected circumoral membrane and by the oval amphids not reaching the extreme anterior end;D. yongeisp.n. resemblingD. americanusChitwood, 1936, but differing from it by the longer and more slender spicules, by the presence of fine spines on the secondary rings, by the head‐shape without a truncated anterior end and by the almost circular am

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1974.tb00821.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractInvestigations of the ground water of the French Mediterranean coast gave 28 different species of harpacticoid copepods. Among them, six species are new to the French coast and three species and one form are described as new, viz.Ectinosoma mediterraneumsp.n.,Sigmatidium rouchisp.n.,Ameira atlántica mediterráneaforma n., andTaurocletodes gallicussp.n. Comparison of the harpacticoid fauna of the French coast with other marine districts shows close relations to the fauna of the Black Sea, while the relations to the Atlantic coast (Portugal) and the Baltic Sea (Bay of Kiel) are only remote. A genus is established,Taurocletodesgen.n.Sigmatidium noodtisp.n. is described from the Sea of Marmar

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1974.tb00822.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY