178 J. T. CUNNINGHAM. 
line; round the posterior thicker end of the head is a translu- 
cent protoplasmic body which is produced into a long tail.” 
«In some cases two spermatozoa were connected by their tails, 
aud on the connecting thread thus produced were slight dila- 
tations composed of clear protoplasm. In other cases a cell 
somewhat spherical in shape gave off two processes, one of 
which was the tail of a spermatozoon, while the other termi- 
nated in a point, the head of the spermatozoon belonging to 
the process having probably become detached in the operation 
of teasing. There were also seen cells in which were present 
one or more structures resembling the heads of spermatozoa ; 
these heads had, however, no tails.” “It is evident that the 
cells and spermatozoa described were derived from the sphe- 
rical cells of the testicular capsules. These cells apparently 
develop the heads of the spermatozoa, each of which then grows 
out from its cell, trailing a thread of protoplasm which forms 
the tail. The curious thing about the spermatogenesis observed 
in Myxine is that the spermatozoa are attached to the spermato- 
blast by their tails, and not by their heads as usually occurs.” 
It will be seen that the results described in the present paper, 
though more detailed and complete, are in no respect in con- 
tradiction to the statements I have just quoted from my former 
paper. But Dr. Nansen, after quoting the above passages, 
writes thus :—‘‘ Those strange statements are completely erro- 
neous as regards the structure of the normal spermatozoa, as 
also the process of spermatogenesis; my investigations have 
led me to no such surprising conclusion, as will subsequently 
be seen, though the testis and spermatogenesis of Myxine are in 
several respects very remarkable.” 
The account of the spermatogenesis which Dr. Nansen 
offers in substitution for mine is as follows:—The spherical 
cells which completely fill the unripe capsules he calls sper- 
matocytes, a term therefore synonymous with spermatoblasts 
in my former description. When the spermatocytes have 
become reduced by subdivision to a certain size the testicular 
capsule is rapidly enlarged, and the spermatocytes are isolated 
from one another. ‘The spermatocytes, however, continue to 
