摘要:

SUMMARYA four‐year study was conducted on breeding populations of Green Sea Turtles,Chelonia mydas(Linn.), in Malaya and Sarawak. The area of study was confined to the South China Sea (Sunda Shelf) coasts of the two countries. The history of the exploitation of sea turtle populations for eggs in the Muslim areas of Malaysia is reviewed; compared with other parts of the world where turtles are killed for flesh and fat, the populations in Malaya and Sarawak appear to have suffered little reduction in size. The general aspects of the marine environment and the different types of sea turtle breeding beaches in the area are described.Chelonia mydastends to build up large breeding concentrations around a small number of beaches, with only limited use of other beaches in the region. Possible causes and adaptive features of the observed situation are discussed. The type of beach utilised by large breeding concentrations of Green Turtles is described, and several particular beaches are described in detail.The process of nesting is described at length, drawing on extensive field notes made over a four‐year period. Particular attention is paid to behavioural aspects of the nesting process and to their possible adaptive significance. Female turtles approaching the beach for nesting are very shy while still in the water and still able to make a rapid escape; they show a clear set of reactions to visual stimuli. With progression up onto the land and isolation from the aquatic environment, the turtles show progressively less response to alarm stimuli. Ihe mechanics of terrestrial locomotion and of the various nesting activities are described, along with discussions of inhibitory and initiatory stimuli which appear to govern the different stages in the process. A table is presented showing the timing of the nesting process in three selected observations on individual females.Courtship and copulation inChelonia mydasare described as they were observed in Malaya and Sarawak.2,720 adult female turtles were tagged on three islands off Sarawak, where the Sarawak Government operates a turtle egg industry. Through the cooperation of the industry, statistical studies were carried out. Methods of tagging are described and pertinent features of the statistical work are discussed The recorded annual egg production from the three islands averages slightly less than two million eggs a year, with a recorded minimum of 700,000 and a maximum in excess of three million eggs.While there is no non‐breeding season in Sarawak, there is a pronounced annual cyclical variation in the intensity of breeding, with a marked heavy season around June, July, and August. The absence of a non‐breeding season is considered to be related to the virtual lack of any marked annual variation in temperature. The existence of a definite peak breeding season is thought to relate to the adaptive advantage of a habit of synchronous breeding aggregation in a widely ranging species. The timing of the peak breeding season appears to relate to the period of the Northeast Monsoon, which brings relatively inclement weather from November through February.The development and decline of the breeding season as shown by egg production figures from the industry shows a remarkable consistency through “good” years and “bad”. While presumably located in time to occur when monsoon effects are minimal, it does not show correspondence to yearly fluctuations in the timing of the monsoon. The per cent contribution of each calendar month to the annual total egg production tends to remain constant regardless of whether the monsoon periods preceding or following are early or late.Individual tagged turtles returned repeatedly to the same beach to nest. Of 5,748 records of returning tagged females only 3–7 per cent failed to return to the same island previously used, despite the fact that two of the islands were only about 500 metres apart.Female turtles nested six or seven times in a season at intervals of about 10 days. Records showed a maximum of 11 successful nests made by a single individual. 8,147 clutches of eggs averaged 104‐7 eggs per clutch, with a Standard Deviation of 1–31.The return in 1956 of numbers of the turtles tagged in 1953 indicates a three‐year breeding cycle in the Sarawak turtles, and provides evidence that individuals are able to make their way back to the same nesting grounds after the long absence.The environment of the incubating nest is described and the hatchery procedures practised on the Sarawak islands are outlined. A special series of nests was transplanted to the industry's hatchery enclosure for studies on incubation. Although surface sand temperatures underwent a diurnal fluctuation of as much as 23oC, at the depths where eggs were deposited the measured temperature never fluctuated more than about 2oC. Incubating nests showed a progressive temperature rise due to the metabolic heat produced by the developing embryos, reaching temperatures as high as 35oC. by the time of hatching. Records of 354 hatchery nests showed an average of 47 per cent of the transplanted eggs resulting in hatchlings which emerged to the surface. Recorded intervals between oviposition and time of emergence of young turtles to the surface varied seasonally from an average of about 70 days during the latter part of February to an average of about 54 days during the period June to October.The process of emergence of the hatchling turtles from their subterranean chamber and their movement to the sea is described.The available data on growth rate and age of maturation is assembled and discussed. It is concluded that Asian Green Turtles probably mature in from four to six years. The carapace measurements of 200 adult females from Sarawak are plotted on a graph; the weights and carapace measurements of ten females are given in a table.Predation upon incubating nests and upon turtles at all stages is discussed. Ghost Crabs(Ocypodasp.) were the most serious observed menace to incubating nests in the areas studied. The heaviest predation observed on hatchling turtles was by Ghost Crabs and small sharks. There is little predation by sea birds on the Malaysian beaches. Several large Tiger Sharks(Galeocerdosp.) were caught off the Sarawak islands; two of these had the remains of adult sea turtles in their stomachs.The various parasites and commensals found on turtles during the study are reported; observations are made on the burrowing parasitic barnacle,Stephanolepas muricata, and its apparent tumour‐inducing proclivities.The paper concludes with an analysis of the problem of scientific management of wild populations of Green Turtles. It is concluded that exploitation for eggs is more logical, more profitable, and more amenable to management techniques than is explo

ISSN:0370-2774    

DOI:10.1111/j.1096-3642.1958.tb00583.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

SUMMARYThe type material of Boulenger'sMoerisia lyonsihas been examined, and the characteristics of the hydroid and its medusa have been compared with those of the lower corymorphines and with other species of the Moerisiidae.An evaluation of the characters of the family reveal that its affinities lie with the suborder Capitata of the Anthomedusae (Athecata), and its nemato‐cyst armature, a tricnidome of stenoteles, desmonemes and atrichous haplonemes, confirms this.A new superfamily, the Moerisioidea is created within the Capitata to take this family; its affinities he with the more primitive Tubularoide

ISSN:0370-2774    

DOI:10.1111/j.1096-3642.1958.tb00584.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

SUMMARY1Four occupied nests, which differ in form and environment, ofP. aethiopicusare described from Lake Victoria. These constitute the first definite records of the nests of this species. Evidence is adduced which strengthens the possibility that certain structures previously thought by other authors to be nests were in fact those of lung‐fishes.2The oxygen content of one nest was determined and found to be low, probably never exceeding 3 p.p.m. During the breeding periods studied, the modal day water temperature was 23oC. and the temperature range 17‐8oto 25‐0oC. The least diurnal temperature variation was 0–5oand the greatest 3–6oC.3From one nest over 5,000 larvae were recovered and from another (incompletely sampled) more than 2,000. Some broods showed a distinct fractioning into several ontogenetic stages. It is concluded that fractioning is attributable to slight initial differences in the time of fertilization and reinforced by individual variation in developmental rates. The scanty data available suggest that more than one female spawns in a nest.4LarvalP. aethiopicusbegin air‐breathing when they have reached a length of 23 to 25 mm. It seems probable that whilst the larvae remain in the nest they are not dependent on aerial respiration.5In its external features, the embryology ofP. aethiopicusclosely resembles that ofP. annectens.Slight differences in ontogeny are discussed. The ova, embryos and larvae ofP. aethiopicusare larger than those ofP. annectens, and have a slower‐ developmental rate. Also, the larvae attain a larger size before the yolk is fully resorbed.6Atca23oC. youngP. aethiopicusremain in the nest for fifty to fifty‐five days. Pre‐hatching development takes about fifteen days; thereafter the young grow to a length ofca35 mm. in forty days.7Post larvalP. aethiopicuslive actively in the matted papyrus roots and the root systems of swamp grasses. There is no evidence to support an earlier idea that they pass the first year of life in a quiescent condition.8The external gills are ciliated. Data relating to the development and subsequent necrosis of these gills is reviewed and summarized.9The breeding cycles ofP. aethiopicusin Lake Victoria are imperfectly known. Observations made on ovarian conditions indicate a peak breeding season from November to April. Occupied nests were found in this period, and in September. This latter nest suggests that spawning may also occur during unseas

ISSN:0370-2774    

DOI:10.1111/j.1096-3642.1958.tb00585.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

SUMMARY1Haliphysema tumanowicziiBowerbank, is an attached foraminifer and the natural variation described is such that the following forms are probably synonyms of it;H. primordialeHaeckel,H. echinoidesHaeckel,H. globigerinaHaeckel, andH. advenaCushman.2An unattached form ofH. tumanowicziiis described which is released from the attached animal. The unattached individual moves over the substratum and eventually settles and forms the basal disc. This newly attached stage becomes a typical attached individual.3The test wall is composed of sponge spicules and other foreign matter cemented together with an acid mucopolysaccharide. On the inside of this wall, in the basal disc and first quarter of the pedicle, there is an organic sheath composed of a mucoprotein. This component is flexible and enables a form such asH. tumanowicziito survive the rough conditions of the littoral zone.4Multinucleate and uninucleate individuals are recorded among both the attached and unattached forms.

ISSN:0370-2774    

DOI:10.1111/j.1096-3642.1958.tb00586.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

SUMMARY1The structure of the head in the nematode family Subuluridae has been studied comparatively and the results obtained used as the basis of a new classification.2The three structures at the base of the buccal cavity are shown to be not teeth, as they are commonly described, but modifications of the anterior end of the pharynx. These modifications are of two basic types: one which is lobed and spirally arranged and one which bears an elaborate arrangement of tooth‐like structures and flanges on the inner surface.3It is shown that at least three parts of the head are of value in systematic analysis: the shape of the mouth opening, the cross‐sectional shape of the buccal cavity and the structure of the pharyngeal portions.4The various structures are analysed throughout the family, and are shown to vary along three evolutionary lines which show a high degree of parallel evolution leading to complex mouth openings with lip‐lobes in all three. It is suggested that this trend towards a complex mouth is associated with increasing efficiency of the mouth as a holding organ.5It is shown that the so‐called ‘double’ buccal cavity, commonly reported fromSubuluraspecies, has always been reported because of a misinterpretation of the pharyngeal portions, due to the reduction of their musculature leading to fully cutieular portions.6The nine genera of which the family is composed, two of which–Prima‐subuluraandTar subulura–are new, have been grouped into three subfamilies, of which one–Allodapinae–is new, on the basis of the analysis of the head structure, in conjunction with other previously better known characters.7The genera are grouped as follows: Subulurinae with three genera,Subulura, OxynemaandLabiobulura; Allodapinae subfamily nov. with two,AllodapaandAulonocephalus; Parasubulurinae with four,Parasubulura, Primasubulura, TarsubuluraandLeipoanema.8As far as possible nominal species have been referred to these various genera on the basis of published descriptions as well as a study of specimens.9Since most of the rearrangements suggested in this paper are based on the structure of the head, which has been almost completely ignored heretofore, many nominal species cannot be referred to a genus and a list of thirty such names is given. These names are considered to represent

ISSN:0370-2774    

DOI:10.1111/j.1096-3642.1958.tb00587.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

ISSN:0370-2774    

DOI:10.1111/j.1096-3642.1958.tb00588.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY