iS 
Fridtjof Nansen. 
[No. 7. 
reason of that I could, for some time, not discover; it will subse- 
quently be seen that I have, perhaps, traced the cause. 
But why do the males occur so extremely seldom? Before 
we attempt to solve this question let us discuss the generative 
organs of the large number of Myxine which were recognized not 
to be true males. On opening large specimens of Myxine, we 
generally find well developed ova in their sexual organs. If we, 
however, take smaller specimens, of about 28 — 32 ctm. in length, 
and examine their sexual organs, we generally find that the anterior 
portion is but slightly prominent, and contains very small and young 
ova, whilst the posterior portion is often very broad and prom- 
inent, is lobate, and has a distinct whitish colour along its margin, 
and has, in all respects, the appearance that we would expect to 
find in a testis; and this it really is. If we take a piece of the 
margin of this portion of the generative organ, tease it, and 
examine it in the fresh state under the microscope, we generally 
find abundance of spermatozoa in various stages of development 
(fig. 4). There can, thus, be no doubt that that portion of the genera- 
tive organ is a real male organ (sections will show this still better 
cf. infra and fig. 11) it is, indeed, strange that CUNNINGHAM has 
so little succeeded in finding spermatozoa. Those young specimens 
(of 28 — 32 ctm. in length) are, consequently, hermaphrodites, with 
quite immature ovaries but well developed testes; and they must 
be able to perform male functions. 
If we now examine, somewhat more minutely, the generative 
organ of the large specimens, which generally contains a number of 
large and well developed ova, we find that those ova occur only 
in the anterior portion of the generative organ, and that the meso- 
arium of this portion is very broad and prominent, whilst the 
membrane corresponding to the mesoarium of the posterior portion 
of the generative organ is very narrow, and carries no reproductive 
elements, neither ova nor spermatozoa (vide fig. 2 & 3j. 
If we examine specimens of Myxine, of sizes between that of 
these large females and that of the hermaphrodite previously men- 
tioned, we will often find specimens in which the anterior portion 
of the generative organ is rather prominent, and contains oblong 
young ova, whilst the posterior portion is of testicular nature and 
not very prominent. These specimens seem, consequently, just to 
be in a transitory stage between male and female state. Indeed, 
on examining a sufficient number af specimens, we will easily be 
able to find every transition-stage from hermaphrodite-maies (as 
