452 ALDEN B. DAWSON 



margin of the pelvic girdle. Dorsocaudally, the common sheaths 

 of the three pairs of caudal muscles and the unmodified median 

 ventral septum limit the mass. 



The ventral portion of the gland mass is continued into the 

 loose subcutaneous connective tissue, extending laterally bej^ond 

 the median area bounded by the hypaxial muscles and, cephali- 

 cally, to cover the surface of the caudal portion of the pelvic 

 girdle. 



In the cloacal mass of the urodeles studied (Heidenhain, 

 '90; Zur Miihlen, '93; Kingsbury, '95) at least three distinct 

 types of tubule have been recognized. They are arranged in 

 definite groups and are known as the cloacal, pelvic, and abdomi- 

 nal glands, respectively. In Necturus both the cloacal and 

 pelvic glands are greatly developed. The homolog of the ab- 

 dominal gland can also be recognized, but it is relatively small 

 and separated into two compact lateral masses (figs. 2, 3, 16, 

 abd.gl.). 



The cloacal-gland tubules form the large median ventral por- 

 tion of the cloacal mass (figs. 11 to 15, cl.gl.). The tubules are 

 long and straight. They extend in a cranial direction and end 

 blindly. The mouths of the tubules open both on the summits 

 of the thin ridges covering the ventral trough of the cloacal tube, 

 and on the tips of the slender internal papillae which fringe the 

 cloacal chamber. On the ridges the tubules terminate in low 

 conical elevations which are arranged longitudinally to form two 

 parallel rows. The terminal elevations which compose these 

 double rows on each ridge are not placed opposite to each other, 

 but have a regular alternating arrangement. The tubules which 

 are connected with the internal papillae also exhibit a regular 

 arrangement, usuallj^ two and occasionally three opening to- 

 gether at the tip of each papilla. 



The large group of tubules comprising the dorsal portion of 

 the cloacal mass has been designated as the pelvic gland. They 

 are sharply separated from the ventral cloacal tubules by two 

 lateral connective-tissue septa (fig. 2, c.t.s.). The pelvic- 

 gland tubules, in contrast with the relatively straight cloacal 

 tubules, are distinctly convoluted. They extend dorsocranially, 



