UROGENITAL SYSTEM OF MYXINOIDS 135 



9. The mesonephric ducts of Mjrxinoids probably possess a 

 secretory as well as an excretory function, as is suggested by the 

 long epithelial cells, the increased surface of these by ridges, the 

 large granules at the distal ends of the cells, and the yellowish 

 bodies in the cells. Also, isolated pieces of the duct contain 

 waste particles hke those present in all parts of the continuous 

 portion of the duct. 



10. The mesonephric ducts of adult male Bdellostomae are 

 larger than those of adult females, and the epithelial ridges 

 within them are larger. 



11. The mesonephric ducts of Myxinoids open separately 

 into the cloaca. 



12. The tubules of the mesonephric Malpighian bodies in 

 Bdellostoma are structm'ally of two types. 



13. \\Tien some eggs in the ovary of Myxinoids attain a size 

 exceeding about 2 nmi. in length, all the smaller eggs are ar- 

 rested in growth until the large eggs reach maturity and have 

 been passed from the body. 



14. ^lany of the small, young eggs in Myxinoids degenerate, 

 forming the 'brown bodies.' 



15. When a mature egg passes from the ovary it leaves at- 

 tached to the mesovarium a 'corpus iuteum,' composed of the 

 outer envelope of mesovarium which surrounded the egg. The 

 corpora lutea degenerate. 



16. After the testis of old males ceases to function, the peri- 

 toneal epithehum which covers the testicular band becomes 

 changed from squamous to columnar; the empty testicular fol- 

 hcles completely disappear, and the band becomes converted 

 into a mass of connective tissue penetrated by blood vessels. 



17. Neither Bdellostoma nor Myxine is a protandric her- 

 maphrodite. 



1&. The m'ogenital system of the North American ]\l}^xine 

 does not present any specific differences from that of the Em'O- 

 pean animal. On the other hand the great difference in size of 

 mature individuals from the two sides of the Atlantic would 

 appear to support the distinctness of M. limosa of Girard from 

 the M. glutinosa of Linneaus. 



