262 JOHANNA M. DIECKMAXN. 



likely to be increased. In the smallest adult in the series, 

 measuring 12.0 cm., the dimensions were i.o mm. each. The 

 above measurements were made from serial sections of the organ. 



DISCUSSION. 



An examination of the spermatheca in different species suggests 

 that the complex forms found in Eurycea, Gyrinophilus, the 

 Plethodons and Desmognathus are developed from the simpler 

 forms (Kingsbury). In Diemyctylus and Necturus each tubule 

 opens separately into, or along the margin of a dorsal depression 

 or slit in the cloaca; this slit in Diemyctylus is partially divided 

 into two by a low ridge. The tubules are numerous (25-40), 

 and flask-shaped. In Amblystoma the tubules open, not into a 

 dorsal slit, but into a depression in the dorsal wall, and instead 

 of being scattered, are aggregated and surrounded by plain 

 muscle. Gyrinophilus, retaining the numerous tubules, presents, 

 instead of a depression, a tube, constricted at its neck. Its 

 branching reminds one of the definitely bilateral character of 

 the organ in Diemyctylus. Eurycea, with its occasionally 

 branched l common tube, resembles Gyrinophilus, but has fewer 

 tubules (12-14). The Plethodons and Desmognathus present a 

 further reduction in number of tubules (4-6), and a loss of the 

 characteristic flask shape. 



If these forms be arranged in a phylogenetic series on the 

 basis of this one feature, the form of the spermatheca, the 

 tendency in the ascending scale seems to be, first, the aggregation 

 of the tubules from a scattered position along a dorsal slit, to a 

 group around a common tube, the expanded end of which may 

 or may not be branched; and second, the reduction of the 

 number of tubules and loss of their flask shape. Correlated 

 with these tendencies in the spermatheca, the importance of the 

 glands is diminished. If we except Diemyctylus, the lower 

 members (Necturus and Amblystoma) have both dorsal and 

 ventral glands, though Kingsbury states that the epithelium of 



1 Kingsbury does not describe the branching of the common tube in Eurycea, 

 but I find it in my specimen, and Koehring, who finds it only in her largest animal 

 (90 mm.), regards it as a late development. Possibly the occasional occurrence 

 of branching in this form represents a transition between the branched common 

 tube of Gyrinophilus and the unbranched of the Plethodons. 



