318 
BULLETIN OP THE BUREAU OP FISHERIES. 
having oriented itself on the surface of the egg exploded and penetrated the chorion; 
this happened in three different species of crabs. The capsule of the normally oriented 
sperm exploded while in view, and the nucleus was drawn into the egg, but it was impos- 
sible to distinguish anything whatever within the opaque ovum. He inferred, but did 
not prove, that this series of events represented a true fertilization process. 
Several attempts were made at artificial fertilization of lobster eggs at Woods Hole 
in 1891, but like the experiences of Koltzoff in 1906 they were unsuccessful. There are 
the difficulties of first obtaining perfectly ripe eggs, and, secondly, of meeting the other 
conditions of fertilization in which the secretion of glands from the ovaries, oviducts, 
or integument of the swiinmerets may play a part. I made glycerine extracts from 
the ovaries and oviducts in the hope of finding a chemical stimulus for the sperm, but 
did not succeed, the primary difficulty of getting the organs in the proper state of matur- 
ity being at that time insurmountable. It was impossible, also, to get any secretions 
from the swimmerets by applying electrical stimulation to the ventral nerve chain, 
from which they are innervated. 
THE SEMINAL RECEPTACLE, COPULATION, AND IMPREGNATION. 
The habits of the lobsters at the time of sexual union, so far as at present known, 
have been already described. (See p. 302). We have now to consider how the female is 
actually impregnated, that is, how the spermatophores are transferred by the male to 
her receptacle. According to the account quoted above the transfer is quickly made 
while the female lies on her back, and in the three or four cases observed when her shell 
is soft. 
While no direct observations on the further course of events are as yet available, 
the structure of the spermatophore, the male stylets, and the female receptacle render 
plausible at least the following account, which is purely conjectural. Before proceeding 
with this, however, it will be necessary to examine the secondary sexual structures with 
greater care. The seminal receptacle (fig. 6, pi. xliii) lies on the underside of the female 
immediately behind the opening of the oviducts and between the bases of the last two 
thoracic legs. (Compare p. 301.) It presents the appearance of a light blue shield with 
deep median groove. When examined closely it is found to consist of a pair of wing- 
like processes, the enlarged sterna of the seventh thoracic somite, with a middle piece 
belonging to the succeeding segment wedged between their posterior extremities. The 
lips of the median groove are elastic, and if forcibly depressed are seen to open into 
a membranous pouch, in which the spermatozoa are carried. The pouch is laterally 
compressed and extends directly upward at right angles to the lo'ng axis of the body and 
is supported on the link-work of the internal skeleton. (Tig. 4, pi. xliii, sac.) We 
should notice that this sac, far from being a delicate structure, is well adapted to receive 
rough treatment with impunity. Within, the middle wedge-shaped piece is continuous 
with a pair of calcareous rods which form a solid frame for the posterior and upper 
part (or bottom) of the sac, where they are firmly sutured to the endophragmal skele- 
ton. Within the pouch this sternal bar is prolonged into a stout keel, where it is 
