78 JESSE LE ROY CONEL 



In view of the fact that only two comparatively short descrip- 

 tions of the pronephros of Bdellostoma have been published, and 

 that the mesonephros of Bdellostoma and the entire urogenital 

 system of the North-American Myxine are still undescribed, it 

 seems desirable : 



First, That the pronephros of Bdellostoma be re-examined, in 

 order, if possible, to collect additional data which may illuminate 

 some of the uncertain or disputed points in regard to its structure ; 



Second, That the mesonephros of Bdellostoma be described 

 more fully; 



Third, That the entire excretory and reproductive systems of 

 the North-American Myxine be described and compared with 

 those of Bdellostoma and of the European Myxine, in order to 

 ascertain whether they present any specific differences or add 

 anything to our comprehension of the urogenital system in 

 Myxinoids. 



MATERIAL AND METHODS 



The Myxine used in this study consist of 20 specimens which 

 Were caught at South Harpswell, Maine, during the summers of 

 1914 and 1915. Three of the animals are immature females, nos. 

 7, 17 and 18, measuring 36.5, 33, and 31' cm., respectively. All 

 the other specimens are adults ranging from 50 to 79 cm. and av- 

 eraging 62 cm. in length. Only one specimen is 50 cm. long and 

 the largest eggs in it are 8 mm. long. The next longest specimen 

 measures 55 cm. and its largest eggs are 22 mm. long. 



Twenty-four specimens of Bdellostoma stouti, 9 males and 

 15 females, which were caught at Pacific Grove, California, com- 

 prise the Bdellostoma material. The smallest is an immature 

 male 33 cm. long. The other males are adults, ranging from 36 

 to 42 cm. in length, and all the females are adults which range 

 from 34 to 40 cm. 



All the animals were killed and preserved in 10 per cent forma- 

 hn, and later were transferred to 70 per cent alcohol. 



The study of the pro- and mesonephros was made from sec- 

 tions stained in Delafield's haematoxyhn and eosin. Toto 

 mounts of these organs, cleared in xylol and imbedded in damar, 

 were also used. 



