Genital Systeyn of the lAyxinoidea 75 



larger than the males, most of which were 30-31 cm. long, and seldom more than 33 cm. 

 in length. 



The Schreiners agreed with Cunningham and Nansen that there is a condition of 

 hermaphroditism in Myxine glutinosa. They observed that in most individuals the sex 

 organ is hermaphrodite in structure, being a testis in its posterior one-fourth or one-third, 

 and containing eggs in the anterior portion. They believed, however, that protandric 

 hermaphroditism is impossible in these animals; that the hermaphroditism is of a rudimen- 

 tary, functionless nature, and that the eels are functionally dioecious. They stated that, 

 with his permission, they were permitted to declare that Doctor Dean had come to the 

 same conclusion after examining 200 specimens of Myxine taken at Bergen. 



These authors offered the following explanation of the present condition of the sex 

 organ in Myxine. An effective hermaphroditism really existed in the ancestors of the 

 myxinoids, and self-fertilization occurred. When larger and larger numbers of individuals 

 assembled in the same locality, there arose the necessity for cross fertilization; this was 

 first effected by means of the posterior testicular part of the sex organ developing and 

 functioning at a different time from the anterior ovarian portion. Gradually a dioecious 

 condition prevailed, resulting in pure males and females, but with many intermediate 

 sterile individuals which were functionless either as males or females, during the entire 

 extent of their lives. 



Conel (1917) found a testis present in the posterior portion and small, round eggs in 

 the anterior part of the sex organ in some young specimens (3 1-36. .5 cm. long) of Myxine 

 glutinosa caught at South Harpswell, Maine. Sections of the testis showed that in struc- 

 ture It resembled the young testis as described by Cunningham, Nansen and the Schreiners. 

 An older specimen (62 cm. long) had a testis in the posterior 9.5 cm., and numerous brown 

 bodies in the entire length of the anterior portion of the sex band. These brown bodies 

 represented atrophied eggs. Microscopical examination of sections of the testis revealed 

 many mitotic figures in the cells of about one-half the follicles, but no spermatozoa in any 

 of the follicles. In two older specimens (63 and 67 cm. long) the testicular tissue had 

 been converted by a process of degeneration i-nto a palisade layer of columnar cells, enclos- 

 ing a central core of fibrous connective tissue; there were no foUicles containing sex cells 

 anywhere in the testis; these individuals were sterile, probably because of old age. In 

 the adult females with well developed eggs the posterior end of the sex organ sometimes 

 contained a few small eggs or brown bodies (atrophied eggs), but it was usually without 

 any reproductive elements. Females with large eggs measured from 59 to 64 cm. long; 

 adult males were from 62 to 67 cm. long. From these facts it was concluded that Myxine 

 could not be a protandric hermaphrodite. 



