CLOACAL GLANDS OF MALE NECTURUS 455 



Heidenhain ('90) observed a like mass of nerve tissue occupy- 

 ing a somewhat similar position in the male Triton and, accord- 

 ing to him, it is found only in the males. He was in doubt as to 

 the function of the ganglion, but interpreted it as being a ter- 

 minal enlargement of the ganglionated plexus associated with 

 the kidneys, and suggested that it might be a portion of the 

 adrenal system which is more or less diffuse in urodeles. "Wo- 

 hin diese Ganglienmassen zu rechnen sind (Nebenniere?), ist 

 mir unbekannt" (p. 190). In some specimens of Necturus I 

 have found scattered cells which exhibit a specific affinity for 

 chromium. 



The tubular glands extend deep into the cloacal wall, of which, 

 as has been already stated, they form the most conspicuous part. 

 In the dorsal portion of the wall the tubules of the pelvic gland 

 obliterate the sharp differentiation of the muscularis into two 

 layers, and the muscle fibers are irregularly arranged and inter- 

 woven, forming with the intermingled connective tissue a dense 

 fibromuscular stroma in which the secreting tubules are imbedded. 

 Some of the muscle cells of the stroma, however, are arranged 

 circularly about the numerous tubules to form delicate muscu- 

 lar tunics. 



The tubules of the cloacal gland, on the other hand, while as 

 large and closely packed as those of the pelvic gland, do not pro- 

 duce such a decided rearrangement of muscle fibers, so that, in 

 the ventral portion of the cloacal wall, a circular as well as a 

 longitudinal layer can usually be distinguished. The tubules 

 pierce only the circular muscle layer and are imbedded in a fibro- 

 muscular stroma similar to that described for the pelvic gland. 

 Each tubule is also surrounded by a delicate layer of circularly 

 arranged muscle cells. The ventral portion of the longitudinal 

 coat of muscle fibers is not invaded by the cloacal tubules, but 

 persists as a compact layer, arranged as a fiat sheet to cover the 

 ventral or external surface of the cloacal gland (figs. 11, 12, 13, 

 14). In the region of the cloacal chamber the definite arrange- 

 ment of the smooth muscle into layers is gradually lost and the 

 fibers are mingled with the connective tissue of the cloacal wall. 



