:78 



SCIENCE. 



[N. S. Vol. IX. No. 222. 



has been and how niiich work has been ac- 

 complished. Aljout one hundred and fifty 

 new determinations of atomic weights have 

 been made in the last twenty j^ears. Still 

 a great deal more \\oy\l remains to be done. 

 F. P. Vexable. 

 University of North Carolina. 



HERJIAPHRODiriSM JX OSTREA LURIDA. 



While doing some work for the United 

 States Fish Commission, during the summers 

 of 1897 and 1898, to determine the possi- 

 bility of propagating Eastern oysters on the 

 Oregon coast, I had an excellent oppor- 

 tunity to study the question of the sex of 

 this West coast oyster. To the best of my 

 knowledge, this question has never been ap- 

 proached hitherto. 



During the spawning season of 1897 in- 

 dividuals emitting sexual products which 



proved under a magnifier to be in some 

 cases sperm and in other cases eggs were 

 carefullj' labelled and separately preserved 

 in different media. As in Ostrea Virginica, 

 there is no possibilitj^ of mistaking the 



identity of these sexual products obtained 

 from the viscei'al mass ; even with the 

 naked eye the granular appearance of the 

 eggs is distinct and pronounced, and the 

 thick, creamy consistency of the non-granu- 

 lar male fluid can never be confounded 

 with them. 



In my notes for 1897 there is no mention 

 of finding ova mingled with spermatozoa in 

 the examination of living products with the 

 microscope. But, after staining and sec- 

 tioning a number of individuals, a/Z oj which 

 are labelled males, I almost invariably found 

 ova in the generative follicles, and amongst 

 them I observed small, deeply-stained bodies 

 in dense masses, which I was led to conclude, 

 even on a preliminary examination, were 

 masses of spermatozoa (see Fig. 1, Camera 

 luclda drawing B. & L., 0„ 1. Obj. i). This 

 belief was strengthened on using a yV hom. 

 imm.,by which I could see occasional faint 

 projections from the small bodies referred 

 to, which projections I assumed to be the 

 tails of the spermatozoa, the dots repre- 

 senting the nucleated heads. The finding 

 of ova in these sections was, of itself, start- 

 ling, for when alive and tested for sex thej' 

 gave unmistakable evidence of being males. 

 In the figure, which only represents a por- 

 tion of one generative follicle, four of the 

 ova show germinal vesicles. 



This season I gave more pai'ticular atten- 

 tion to the microscopic examination of liv- 

 ing specimens. The seemingly conclusive 

 results from the study of many individuals 

 is here given. In a specimen of fluid from 

 a male I observed, among free spermatozoa 

 covering the field, collections of sperm cells 

 which I will call ' sperm masses.' Each 

 sperm cell in a mass possessed a tail, and 

 these tails, actively waving to and fro in 

 the salt water under the cover slip, caused 

 the mass to move about. These tails were 

 seen fairly well with a ^ obj. These living 

 sperm masses I regard as identical with the 

 deeply-stained masses seen among the ova 



