1889.] Zoology. I 823 
but well developed testes, and they must be able to perform male 
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 an- 
terior portion of the generative organ, and that the mesoarium of this 
portion is very broad and prominent, whilst the membrane corres- 
ponding to the mesoarium of the posterior part of the generative organ 
is very narrow, and carries no reproductive elements, neither ova nor 
spermatozoa. 
If we examine specimens of Myxine, of sizes between that of these 
large females and that of the hermaphrodite previously mentioned, we 
will often find specimens in which the anterior portion of the genera- 
tive 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, to be in a transitory state between 
male and female states. Indeed, on examining a sufficient number of 
specimens, we will easily be able to find every transition stage from 
hermaphrodite males to fully developed females ; and the rule seems to 
be that the larger the s])ecimen is, the more are the female organs de- 
veloped, and the more do the male organs disappear. 
From wliat has l)een stated above, we seem already entitled to con- 
clude, that Myxine is generally or always (?) in its young state a 
male ; whilst at a more advanced age it becomes transformed into a 
female. Indeed, I have not yet found a single female that did not 
show traces of the early male stage. 
Upon the whole, it must ])e admitted that there is a strange irregu- 
larity in the occurrence and extension of the male and female organs 
in Myxine. Myxine seems to me to be an animal which, in sexual re- 
spects, is just at present in a transition stage ; from what and to 
without yet reaching, that mode of reproduction which is most profit- 
able for it in the struggle for existence.— Fridtjok Xax>kx. hi Ber- 
gen's Museums Aarsberetning for 1888. 
Birds Killed by Electric Lights at Girard College, Phil- 
adelphia.— During the spring and fall migrations of birds many dead 
birds are seen near the electric towers in the grounds. In the last three 
weeks (piite a number have been found, though not so many as last 
year, when a whole flock struck the electric tower at Ridge and South 
College avenue, in their migration to their winter quarters to the South. 
