kidney in abstiacting excretory matter from the blood ano in concentrat- 

 ing ir in masses which can be passed readily from the body She also showed 

 that this gland is present though in less developed form, in recently hatched 

 drills The digestive gland some of the cells of which in some gastropods per- 

 form an excretory function in Urosalpir-x may function in this manner to a 

 limited degree since Fretter notes that in the drill the cells of the digestive gland 

 appear to be extremely simple in structure . 



Reproductive System 



The sexes in the drill are separate and according to Federighi (1931b), 

 who studied 1, 121 drills in the Woods Hole area, they occur in about equal 

 numbers, but females are slightly wider and attain a greater height than males. 

 Stauber (1943) however, found that a greater proportion of large drills collected 

 in Delaware Bay were females, although he did dissect some males over 30 mm 

 in height which suggested to him that a certain amount of protandry may occur , 

 Table 1 gives a representative sample of Stauber s measurements relating height 

 and sex in Urosalpinx. Because of difficulty in handling, no drills smaller than 

 17.6 mm, n height were included The doubtful column represents drills too 

 badly crushed after opemng to make diagnosis of sex satisfactory. Stauber notes 

 that although the mear height of the males and females does not differ significantly 

 in Table 1, numerous repetitions of such data give a similar distribution of height 

 Stauber s measurements were made on drills trapped in April; whether drill trapping 

 is selective for either sex is not reported, but should be kept in mind here 



The large curved penis in the male, though not easily seen, the yellow to 

 orange colored female gonad, and the whitish male gonad (Federighi. 1931c; Cole, 

 1942) afford reliable characters by which the sexes may be distinguished. 



There are no studies available on the reproductive organs of U. cinerea , 

 Fretter (1941) presents an admirable treatment of this subject in the closely re- 

 lated English drills Ocenebra and Nucella; and since in general the structure and 

 functioning of this system in these three closely related drills may be similar, 

 it is instructive to briefly review Fretter s studies here. 



The male reproductive system includes a testis where sperm are formed; 

 a ciliated duct, the vas deferens, which carries sperm to the large prostate gland 

 where seminal fluids are added; from the prostate gland sperm are transported 

 along another ciliated duct to the penis which transfers them to the vagina of the 

 female during copulation. Andrews and McHugh (pers. com ) report that examina- 

 tion of drills by cracking off the shell revealed that Urosalpinx as small as 9 mm 

 in height possess a well developed penis . 



26 



