601 
of Edinburgh, Session 1885-86. 
escapes. The very young eggs are transparent and spherical, and 
show a distinct germinal vesicle in the fresh condition. As the 
eggs elongate the germinal vesicle passes to one end, but the yolk 
soon develops and conceals that structure from view. 
Male Elements of Reproduction. — Professor Steenstrup, in the 
paper above mentioned, says that no one seems to have seen a male 
Myxine. This is not quite correct, for Johannes Muller, in the last 
volume of his Verglerichende Anatomie der Myxinoiden , published 
in 1845, describes the testis of Myxine in a somewhat vague manner, 
but in such a way that, from my own experience, I have no doubt 
that he really had a young male specimen under his hands. The 
males are very rare ; out of all the specimens which I have examined 
only ten have been males, and these are all immature. It is extremely 
difficult to distinguish between a male and a very immature female ; 
in most cases I have only been able to do so by microscopic examina- 
tion of the generative organ. The testis is similar in general 
structure to the ovary, but the free border is slightly more thick- 
ened than in the latter organ, and has the gelatinous appearance 
characteristic of testicular tissue. When examined with a low 
power the thickened edge is seen to contain a number of more or 
less spherical capsules, and these on compression are seen to be filled 
with rounded polygonal cells. When the capsule is burst the cells 
escape, and are then seen to be spherical, extremely transparent, and 
provided with a large nucleus. It is easy to conclude that these 
cells give rise to spermatozoa. The spermatozoa of Myxine hitherto 
have never been seen or described. 
Hermaphrodite Specimens. — After identifying the immature 
males, I found that in nearly every specimen in which the eggs were 
very immature the posterior end of the sexual organ was similar 
in structure to the testis. The testicular portion is usually much 
smaller than the ovarian, and occupies about 2 inches of the pos- 
terior end, but sometimes extends further forward. These herma- 
phrodites are almost as common as the females. The most curious 
fact about the hermaphrodite forms is, that in two of them I have 
found the early stages of the development of spermatozoa, although 
in the males I never found anything but the spherical cells above 
described. In one of these two specimens I found spermatozoa within 
the testicular capsules, but these spermatozoa were few in number 
