ZOOLOGY. 717 



examination of the subject, and J. Carriere, J. T. Oattie, and T. Bar- 

 rois have all expressed their opposition to the hypothesis in question, 

 basing their antagonism on the examination of many species, including 

 most of those species to which pores have been attributed. The con- 

 clusions are summed up by Barrois : " No pores exist for the introduc- 

 tion of water into the circulation; the only pores of the foot are those 

 connected with the byssus organ, which never communicates with the 

 interior of the foot. The blood may have water introduced into it, but 

 this may be effected by osmosis, or iu some manner not discussed." 

 (Science, vol. in, pp. 130-131; J. B. 21. 8. (2), vol. iv, pp. 212-213.) 



The European Oyster. — An elaborate series of reports on the oyster 

 and its culture in the Netherlands is being prepared under the auspices 

 of the Zoological Society of that country, and the first, by P. P. C. Hoek, 

 ffie secretary of the society, appeared in 1883. It enters fully into the 

 anatomy and physiology of the species, but only that portion relative to 

 its generation need be noticed here. The ova are fertilized by sperm 

 from other individuals, with which the circumambient water must be 

 charged, and which enters into the mantle cavity and genital ducts. 

 Th^ ova are matured and cast together at about the same time, but the 

 sperin appears to be more gradually matured and spent. The bivalves 

 are about two years old before they have broods, and they are most 

 prolific at the age of some four or five years. The males are more 

 numerous than the females. The ova, when discharged, having been 

 fertilized in the ovary, have already undergone the first stage of seg- 

 mentation in their development. After propagation the exhausted par- 

 ents rest, and a period follows in which no sperm is reproduced. It is 

 claimed that a large proportion of the spat of the Eastern Schelde (where 

 the observations were chiefly made) was probably derived from others 

 than the oysters of the cultivated beds. As a corollary it is contended 

 that culture seems to injuriously influence and impair the reproductive 

 powers of the oyster. There is a somewhat inverse relation between 

 the development of the liver and the generative organs, shown by the 

 fact that the former is much more developed in the old after the repro- 

 ductive faculty has decreased. 



Gastropods. 



Deep-sea Solenoconchs. — The order of Solenoconchs, represented by 

 the tooth-shells (Dentalium) are much more numerous in the deep seas 

 than in the littoral faunas, and form indeed quite a characteristic feature 

 of the Bassalian realm. Professor Fischer considers that they are espe- 

 cially adapted for life on the bottom in the midst of the ooze which covers 

 it. There they prey upon the Foraminifera which abound around them 

 and which they secure by means of their filaments. According to Profes- 

 sor Fischer's experience, the best represented species is the Dentalium 

 agile, originally described by Sars from individuals dredged in the 



