ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 175 



160-177 mm., but in capillary tubes only about 100 mm. There is no 

 evidence that the ova attract the sperms at a greater distance than 1 mm. 

 No evidence was obtained to show that the presence of one set of sexual 

 elements in the water stimulated an animal of the opposite sex to dis- 

 charge its elements, either in limpet or urchin, nor could the existence 

 of any sexual attraction be demonstrated. It would appear that the 

 active sperm possesses some power of nutrition ; for sperms were found 

 to live longer in water containing sterilised bouillon than in water 

 without this addition. 



Development of the Testis.*— Br. J. Foulis has studied the origin 

 of the seminiferous tubules, especially in the deer. The young testis is 

 a sub-peritoneal outgrowth from the primitive germinal ridge, pushed 

 out, as it were, into the form of an elongated body by certain continually 

 growing tubules which pass into its b>se from tho Wolffian body through 

 the centre of a stalk-like connection of peritoneum. He seeks to show 

 that the seminiferous tubules are thus derived from the terminal end of 

 the Wolffian duct. If the Wolffian ducts are epiblastic in origin, the 

 same will be true of the seminiferous tubules, and probably of the 

 epithelial cells lining them. 



Embryology of Marsupials. f — Mr. J. P. Hill has been enabled to 

 make some further observations ou this subject, which supplement his 

 previous account of the process of parturition and the characters of the 

 embryonic membranes. He has studied the genital organs of a female 

 of Perameles obesula containing embryos of a stage later than that pre- 

 viously described by him as stage D ; and as the female proved to have 

 been in her first pregnancy, he was able to make some additional ob- 

 servations on the genital organs. As to the foetal membranes, no strik- 

 ingly new facts have been brought to light, save the demonstration of 

 the fact that the yolk-sac wall persists throughout intra-uterine life. 

 From the structure of the genital organs it appears that before the first 

 parturition there are two vaginal cul-de-sacs ; after parturition these 

 two unite to form a common median vagina, opening into a narrow cleft 

 — the median jjseudo-vaginal passage — which lies in the connective- 

 tissue between the lateral vaginal canals. Further, the author finds 

 that in Dasyurus river rinus there is a placental connection, probably of 

 yolk-sac origin, which originates in a fashion similar to that seen in 

 Perameles. The paper also includes a brief description of the foetal 

 membranes of Macropus par ma, which in essentials is the same as those 

 of other authors who have studied Macropods. The point ( f importance 

 is the small size and rudimentary condition of the allantois — a condition 

 which must now be regarded as undoubtedly secondary. 



Development of Mouse.} — Mr. J. W. Jenkinson has studied the 

 early stages of development in this auimal, of which an account had been 

 previously given by Robinson, § and criticises the statements of the latter 

 author, which he believes are based on a misinterpretation of sections. 

 The paper may be regarded as consisting of two parts: — (1) a detailed 

 criticism of Robinson's statements and figures, and (2) a criticism of the 



* Trans. Med.-Chirurg. Soc. Edinburgh, 1890, 20 pp. (7 pis.), 

 t Quart. Joum. Micr. Sci., xlhi. (1900) pp. 1-22 (2 pis.). Of. this Journal, 1898, 

 p. 180. % Tom. eit., pp. 61-81 (2 pis.). § Op. cit, xxxhi. 



