8 
Fridtjof Nansen. 
[No. v 
Hi sto ri cal. 
To give a circumstantial account of the previous investigations 
regarding the structure of the generative organs in the Myxinoida is 
unnecessary, as it is already done, sufficiently, by previous writers. 
I will, however, especially refer my readers to Cunningham s recent 
paper 1 ) and to Wilhelm Muller's paper (1875 pp. 107— 109) 2 ). 
I will devote special attention to those two papers only, (the 
latter of which is not mentioned by Cunningham in his paper 
referred to above) mentioning at same time, quite shortly, the other 
previous authors on the subject. 
Johannes Muller is the first zoologist who has given a de- 
scription of the minute structure of the generative organs of Myxine. 
He says that »the sexual organs hang in a long peritoneai fold on 
the right side of the mesentery«. He gives a tolerably correct de- 
scription, illustrated with figures of the ovary and of the young 
eggs of Myxine, as well as of Bdellostoma. He also describes 
» testes «, and gives illustrations of them, but, judging from his de- 
scription and figures, I think it is very dubious whether he has 
really seen testes; his description suits just as well, or perhaps 
better, for young undeveloped ovaries, when he says: »The testes 
consist of a number of round and roundish long grains, which 
resemble the eggs«. As will subsequently be shown, the testes 
have a different, and more granular, appearance, and in their appear- 
ance dififer, considerably, from the young ovaries. 
In 1859 a niature egg of Myxine was described and illustrated, 
for the first time, by Dr. Allen Thompson in »Todds Cyclopædia 
of Anatomy and Physiology«, but unfortunately this author does 
not state where, or how, he obtained the egg he has examined. 
J ) Vide, list of literature 1886. 
2 ) Vide, list of literature 1875. 
