CLOACAL GLANDS OF MALE NECTURUS 457 



not have a ciliated epithelium. The more cephalic papillae 

 are covered by a two-layered mucous epithelium, while those 

 nearer the external aperture have a stratified epithelium of 

 three to four layers similar to that covering the unmodified 

 wall of the cloacal chamber and the cloacal lips. 



DISCUSSION 



In Xecturus, spermatozoa are regularly found within the 

 cloaca of the female. The transfer of spermatozoa from the 

 body of the male to that of the female is supposedly accomplished 

 by means of spermatophores. In Crypt obranchus, however, 

 fertilization is external and the sperms are expelled into the water 

 without the formation of spermatophores (Smith, '07). In 

 Diemyctylus (Jordan, '01) and Amblystoma (Wright and Allen, 

 '09) spermatophores are deposited and the female by her own 

 activity must ensure the entrance of the spermatozoa into her 

 cloaca. In the Tritons and in Desmognathus (Wilder, '13) 

 the transfer of the spermatophore is accomplished by a venter 

 to venter copulation. 



Just what role the greatly developed cloacal glands of the 

 male Necturus play in the mingling of the sexual products it is 

 difF.cult to say. The success of the spermatophore method de- 

 pends largely on the proximity of the female. In some urodeles 

 specialized integumental glands are believed to attract the oppo- 

 site sex. Xo such glands have been found in the integument of 

 Necturus (Dawson, '20). Some of the cloacal glands, accord- 

 ingly, may perform this function. The abdominal glands, on 

 account of their superficial position, would not apparently enter 

 into the spermatophore formation. They may, therefore, liber- 

 ate chemicals which diffuse through the water and attract the 

 female or, if the spermatophores are transferred directh' to the 

 female by a venter to venter copulation, these glands, together 

 with the external papillae on whose median surfaces they open, 

 may assist in overcoming the difF.culties involved in sperm trans- 

 fer in the water, the external papillae forming a kind of intromit- 

 tent organ. 



