摘要:

The proboscis ofMangeliais a highly specialized and modified organ involving a terminal sucker and an additional permanent sheath within the proboscis sac which has been named the supporting sheath. Its structure can be derived from the condition seen in the Conidae by supposing that the folds formed during the retraction of the proboscis in these animals become lengthened to form one single permanent fold inMangelia. The anterior part of the alimentary canal and the organs associated with it are similar to those found in the Conidae, and include a highly coiled poison gland which opens ventrally into the oesophagus immediately posterior to the opening of the buccal sac. It is pointed out that the poison gland is the coiled tube and that the swollen proximal end of the gland is a non‐glandular propulsive organ, the muscular bulb, and that the true poison gland duct is a short distal passage joining the tubular gland to the buccal cavity. The frequently stated belief that the poison gland is derived from the gland of Leiblein is discussed and the possibility that it represents the ventral salivary glands is mentioned. The absence of a pedal sucker and of the ventral pedal gland is noted. The genital ducts are described and found to conform to the general plan seen in the Stenogloas

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1960.tb05850.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

Following a comparative histological investigation of the genital systems of representatives of the four families of the Hygrophila, a standardized nomenclature for the different parts of the female duct is proposed and homologies are suggested.The reproductive systems ofPhysa fontinalis, Lymnaea peregra, Planorbarius corneusandAncylus fluviatilisare described and all four species differ in the relationship of the fertilization pockets to the union of hermaphrodite, male and female ducts. In the Physidae alone, the ova pass into the albumen gland and there is no albumen gland duct, a condition which is similar to that ofSuccinea.The Chilinidae probably stand close to the ancestral condition of the Hygrophila and the prostatic histology ofChilinaresembles that of the Physidae, Ancylidae and Planorbidae, whilst the cells of the prostate of the Lymnaeidae are fundamentally different.The degree of development of the different parts of the oviduct in the four families is illustrated. Oviduct I is a short conduit and oviduct II, which is extensively developed inPhysaandLymnaea, is comparable to the posterior portion of the female tract ofChilina robustior. In oviduct III the fertilised ova are embedded in viscous fluid and enclosed in the capsular membrane and this region of the female duct becomes greatly folded in the Lymnaeidae and Planorbidae to form the oothecal gland. Oviduct III is absent inAncyluswhere oviduct I opens directly into oviduct IV, a region which has a specialized histology. Oviduct IV is also found inPlanorbarius, following oviduct III, and is therefore a common feature of these two families.It is concluded that the genital system of the Physidae is nearest to the ancestral condition, from which the Planorbidae and Ancylidae are later offshoots. The reproductive system of the Lymnaeidae, while retaining several features in common with that of the Physidae, has probably followed a separate evolutionary path.

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1960.tb05851.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

The gannet has well‐developed secondary external nares to compensate for the primary ones which are occluded. It is questionable if this occlusion is a direct consequence of the habit of high diving. Occlusion of the external nares apparently limits the function of the nasal glands as salt excreting organ

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1960.tb05852.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

The conditions under which specimens of the Tasmanian dormouse phalangers,Cercaertus nanusandEudromicia lepida, were found in the field are described. Brief descriptions and measurements of the animals are given.The activity and dormancy of the two species kept in captivity were investigated daily over a twelve month period. There was no prolonged hibernation. Activity and dormancy alternated throughout the year, the longest period of dormancy in the case ofC. nanusbeing twelve days and in the case ofE. lepidasix days.The body temperature of each species during dormancy was about equal to the air temperature. A dormant specimen ofC. nanushaving a body temperature of 12.5°C. took three hours to become fully active, when roused from dormancy. During this period the body temperature rose to 31°C. In the same way a dormant specimen ofE. lepidahaving a body temperature of 17°C. required three hours and forty minutes to become fully active, its body temperature rising to 32°C.The food and feeding habits of both species were studied, and found to be much the same. Insects were preferred but spiders, dead scorpions and even lizards were readily accepted. The flowers ofEucalyptusandBanksiawere pulled to pieces but not eaten.During periods of activity the daily food consumption amounted to about seven per cent of the body‐weight of the animal in each case.The composition of an artificial food on which the animals thrived is

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1960.tb05853.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

The existence of a large non‐breeding gathering of seals in the (Welsh) Dee has been established. Detailed counts for a period of several years are given and certain characteristics of the gathering are describe

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1960.tb05854.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

Changes in the coat and skin of a mouflon sheep were followed from the age of three months to the age of twenty‐one months. The birth coat was shed between four and six months of age and there was a marked moult the following spring. During both these moults the coat was lost as a single mat. The wool of the under‐coat was shed only once during the spring moult, whereas the hairs of the outer coat were shed a second time in summer, but this was less obvious than the spring moult.Details of the histology of the skin and of fibre shedding are given in addition to incidental observations on growth and the ho

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1960.tb05855.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

Collections ofClethrionomys glareolusSchreb. have been made from the mainland of north‐west Scotland and the Islands of Mull and Raasay. The skull of the Raasay vole is larger than that of the other two sub‐species although the proportions of all three are similar. The number of re‐entrants on the inner margin of the third upper molar declines as the tooth wears. On the islands, a higher proportion of newly erupted teeth have three re‐entrants.The three collections differ little in coat colour.Life expectancy is higher and breeding less intense in north‐west Scotland than further south. Comparatively little reproduction is performed by Scottish animals in their first year.There appears little basis for separating the Mull and mainland subspecies ofClet

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1960.tb05856.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

The Senegal galago appears to have an oestrous cycle lasting four to six weeks and recurring throughout the year. It most probably exhibits a post‐partum oestrus. The intensity of sexual activity varies during the year and this gives the appearance of one or more restricted breeding periods. In the Nuba mountains there is a period of intense sexual activity in mid‐December. A well‐developed sequence of changes occurs in the vaginal epithelium during the oestrous cycle. These changes are typical of those seen in other mammals. The corpus luteum of pregnancy, which may become pedunculated, only lasts for about the first third of pregnancy. Twin pregnancies are unc

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1960.tb05857.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

The internal structure and function of the stomach is described for representatives of twenty‐three families of Eulamellibranchia. The stomachs of two of these are assigned to Stomach Type IV and the remainder to Stomach Type V. A detailed analysis is made of structural variation in the stomach in the twenty‐one families with stomachs of Type V and a definition of Stomach Type V is given. The appendix is limited in its occurrence to the Tellinacea and the Adesmacea, which suggests that these two sub‐orders are closely related to each other. It is concluded that Stomach Type IV is an ancestral character which has persisted to the present time in a large section of the Lamellibranchia; it is suggested that there arose from the ancestral stock a separate phylogeny which is characterized by the possession of Stomach Type V. It is concluded that within the phylogeny that is chara***cterized by Stomach Type V it is possible for the stomach to be simplified and to resume secondarily the ancestral form of Stomach Type IV. This is considered to have occurred in the Sphaeriidae, Lucinidae, Thyasiridae, Donacidae and inChama multisqu

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1960.tb05858.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1960.tb05859.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY