52 J. T. CUNNINGHAM. 



bore the same relatiou to the ovum as the egg capsule of ovi- 

 parous Elasmobranchs, and that the two protective structures 

 were homologous. This view has been adopted on Thomson's 

 authority by recent authors ; Balfour, for example {' Comp. 

 Emb/), simply refers to Thomson's description. I have not 

 been able to ascertain whence Thomson obtained the specimen 

 on which his description is founded. It is evident, as will be 

 seen later, that he only examined the egg externally. 



In 1862, the Academy of Sciences of Copenhagen offered a 

 prize for an investigation which should solve the problem of the 

 reproduction and development of Myxine. The prize was never 

 awarded, no one having undertaken the work, but in 1863 Pro- 

 fessor J. Steenstrup published, as a guide to any who might 

 attempt the research, an account of a specimen of Myxine which 

 contained ripe eggs. Professor Steenstrup began by remarking 

 that no one seemed to have seen males, and of females only 

 those which had young or slightly developed eggs, and that the 

 very young and undeveloped females were as unknown as the 

 males ; that in the literature there seemed to be no record 

 that naturalists had seen individuals of less than 8 or 9 inches 

 long, whilst those large egg-bearing females which had pre- 

 viously been investigated were generally 10 to 13 inches in 

 length. The work of Miiller and Allen Thomson had appa- 

 rently not come under Steenstrup's notice. The rest of 

 Steenstrup's short paper is in substance as follows : 



The females of 10 to 13 inches in length have generally 

 been regarded as females with fully developed sexual products, 

 not without some reason. They have had not only a large 

 number of eggs which were larger than the ripe egg of Petro- 

 myzon, but most of them have had in addition from twelve to 

 twenty eggs which were ^ to | inch long, and 2 to 2| lines 

 broad, and these eggs, which have been situated in moniliform 

 fashion along the margin of the ovary, have been so loosely 

 embedded in its folds that they easily fell out into the body 

 cavity. On account of the interest attaching to the question I 

 made a point of collecting as far as possible all the specimens 

 of Mvxine which I could obtain, for the Zoological Museum, 



