Genital System of the hlyxinoidea 77 



observations have been recorded by previous authors. The investigators of the question 

 of hermaphroditism in the genital system of Bdellostoma are fewer in number than 

 those who have examined Myxine, only four writers have published accounts of their 

 observations. 



Hermaphroditism in Bdellostoma forsteri. — In July 1886, Cunningham read a paper 

 before the Royal Society of Edinburgh in which he discussed briefly the reproductive 

 organs of a number of specimens of Bdellostoma forsteri from Cape Town, Africa, which 

 were in the museum at Oxford. Strange to say no other student of the Myxinoidea has 

 made any further observations on B. forsteri. Regarding his specimens Cunningham 

 (1886.1) wrote as follows: 



I have not yet made a microscopic examination of the reproductive organs of Bdellostoma, 

 but from what I could see by ordinary dissection, it is evident that all the peculiarities which 

 exist in the reproductive system in Myxine occur also in Bdellostoma. A number of speci' 

 mens possessed sexual organs, in the anterior part of which were minute ova, while the 

 posterior part was evidently testicular tissue; and in one or two other specimens the 

 whole organ seemed to be testicular. The small quantity of testicular tissue in a given 

 specimen was also noticeable, as in Myxine. 



Hermaphroditism in Bdellostoma stouti. — As a result of observations made on Bdel- 

 lostoma stouti at Pacific Grove, California, Ayers (1894) concluded that "in all cases each 

 individual is potentially bisexual." He observed that the anterior region of the peritoneal 

 fold is always ovary, while the much smaller posterior region of the fold is the testis. He 

 found spermatozoa in the testicular follicles of many individuals, but found very few 

 females containing eggs in the last stages of ripening. Among the specimens taken by 

 him were some young, as well as large and old, males and females. He wjote as follows: 



Some individuals of Bdellostoma are truly hermaphroditic, having at the same time a 

 genuine testis with ripe sperm and an ovary with eggs nearly or quite ripe [his Fig. 12]. These 

 individuals are rare , so far as my experience goes, but others with the two organs in a more 

 unequal state of development are more numerous. However, by far the largest number 

 of individuals are genuinely male or female. 



He found a preponderance of males among the specimens taken by him; of 309 eels, 

 182 were true males, 121 were females, and 6 were hermaphrodites. Ayers, therefore, 

 believed that functional hermaphrodites exist in small numbers. 



In his excellent paper describing the general embryology of Bdellostoma stouti. Dean 

 (1899) discussed at some length the question of hermaphroditism in Myxine and Bdellos- 

 toma. He offered the following objections to the hypothesis that Myxine is a protandric 

 hermaphrodite. (1) Bdellostoma and Myxine are admitted to be closely related. If, 

 therefore, there are found in Bdellostoma small females which do not have testes, and large 

 functional males without any traces of eggs, the hypothesis of protandric hermaphrodit' 

 ism would be disproved. Dean observed among large specimens of Bdellostoma (38 to 40 



