76 



Bashford Dean Memorial Volume 



The results of the investigations of Cunningham, Nansen and the Schreiners may be 

 tabulated as follows: 



Cunningham 



Found but eight individuals having only 

 a testis in the sex organ (true males), and 

 these were young and immature. 



Mature males with motile spermatozoa 

 are between 30 and 35 cm. in length, and 

 have young, round ova about 2 mm. in 

 diameter in the anterior portion of the sex 

 organ. 



A testis is never present in specimens 

 with eggs more than 4 mm. long. As the 

 eggs grow larger, the testis atrophies. No 

 testicular tissue remains in specimens more 

 than 35 cm. long. 



Anmials over 35 cm. long are females in 

 which the testis has completely atrophied 

 (this length is not absolutely constant). 

 The longest individuals have well devel- 

 oped ova. Does not describe the structure 

 of the atrophied testes. 



Nansen 

 Saw only very few true males, and 

 these were immature. 



Mature males with spermatozoa are 

 28-32 cm. long and have very many 

 young ova in the anterior portion of the 

 sex organ. 



The testis is not prominent in in- 

 dividuals with oblong young ova. As 

 the animal grows larger, the testis dis- 

 appears, and the ovary increases in 

 development. 



The largest animals generally contain 

 large, well developed ova in anterior 

 portion of sex organ, and nothing what- 

 ever in posterior portion. All females 

 show traces of eairly male stage. Does 

 not discuss these traces. 



Myxine is functionally a protandric 

 hermaphrodite. 



Myxine is functionally a protandric 

 hermaphrodite. 



The Schreiners 

 Found that true males are insignificant 

 in number. 



Mature males with ripe spermatosoa 

 vary from 25 to 33 cm. in length. In 

 anterior part of sex organ in most males 

 there is a rudimentary ovary containing 

 quite small eggs which are always 

 abnormal and never develop to maturity, 

 but degenerate. 



If a testis is present in females having 

 normal eggs, it is always abnormal and 

 degenerate, and never was functional. 



Females with mature ova vary in length 

 from 26 to 37 cm. As a rule, females 

 have nothing in posterior part of the sex 

 organ. Any testicular tissue present in 

 posterior part of sex band is always ab- 

 normal and degenerate. Do not discuss 

 degenerate elements. 



Of all the eels examined 13 . 1 per cent 



were sterile. Some of these sterile in- 

 dividuals lacked both testis and ovary; 

 others possessed these in an abnormal, 

 degenerate condition, and were never 

 functional either as males or as females. 



Myxine is structurally hermaphrodite, 

 but functionally dioecious. 



From the review of the literature as given above it can be seen that true male sped' 

 mens of Myxine glutinosa have been but rarely taken in European waters. This fact led 

 Cunningham to believe that the males change into females after functioning as males, 

 and Nansen corroborated him in this. The Schreiners confirmed the presence of a mor^ 

 phological hermaphroditism, but decided that it is not functional. Why functional males 

 are not caught more frequently in the North Sea is certainly very strange. Females exist 

 in large numbers, and since each female deposits from 25 to 45 eggs at a time, many males 

 and much sperm would be required to insure fertilization, especially if, as is believed by 

 all investigators, fertilization occurs after the eggs are extruded from the female. 



HERMAPHRODITISM IN BDELLOSTOMA FORSTERI AND BDELLOSTOMA BURGERI 



In view of the uncertainty as to hermaphroditism in M>'xi?ie glutinosa, an investiga- 

 tion into the condition of the genital system of Bdellostoma would be of special interest, 

 and this needs to be prefaced with a brief review of the literature in order to indicate what 



