THE BATRACillA 01' NOKTII AMERICA. Ill 



CHONDROTUS TENEBROSUS Bd. Giiil. 



(Plate 22-23; 24, figs. 1-3.) 



Cope, Auiericau Naturalist, 1887, p. 88. 



AmbJystoma tmebrosum, Baird and Girard, Proc. Ac. Pliila., 852, p. 174, and U. S. 



Expl. Siii'v., XII., part ii., PI. 31, fig. 1; Cope, Proc. Ac. Phila., 1867, p. 202; 



Straucli, Salam.,p. (i5; Boaleager, Cat. Batr. Grad. Brit. Mus., ed. ii, 1882, p. 49. 

 Xiphonura ientljrosa, Gir., U. S. Expl. Esped., Herp., p. 14, PL i, figs. 9-17. 



This species is especially characterized by its massive frame aud huge 

 size among true salamanders, as well as by other peculiarities, hereafter 

 to be mentioned. 



The skin is less glandular than in A. punctatum or tigrinum, although 

 scattered glands may be detected closely and evenly distributed on the 

 whole back and sides and on the chin. The remaining under parts and 

 snout before the eyes are smooth. 



The head is very massively built, large, broadest behind the eyes and 

 triangular, the sides being nearly straight to the narrow aud rounded 

 tip. The eyes are very large aud prominent, separated by less than 

 two lengths of the orbit, and distant less than one length from the outer 

 nostrils, which are separated by 1^ orbits distance, and placed on the 

 side below the distinct canthus rostralis. The outer nostrils are much 

 more distant than the inner, which are very large, much excavated, 

 and have the external canal occupied by a soft, plaited membrane. 



The tongue is thick aud fleshy, nearly orbicular, but angular anteri- 

 orly. It fills up the lower jaw pretty well, aud is more than half the 

 width of the head. 



The palatine teeth are in two patches only; each very slightly convex 

 anteriorly, coming together at a slight angle, with the apex backward, 

 but separated along the median line. Laterally the patches of teeth 

 form the posterior margin of the inner nares, and do not extend beyond 

 their outer margin. The entire series is thus posterior to the nostril. 

 In younger specimens the series are more transverse, the inner extrem- 

 ities slightly incurved. 



The width of the head is contained 1;^ times in distance to gular fold 

 and 4 times to groin. 



The body is rounded and depressed. As nearly as can be ascertained 

 there are about twelve costal furrows. 



The tail in the two specimens before me is considerably less than half 

 the total length. It is much compressed from near the base, and the 

 edges near the end are quite sharp. It is far short of being as deep at 

 the base as the body. 



The limbs are stout. The digits, the fingers especially, are short, con. 

 siderably depressed, but linear and blunt at the tips. The under sur- 

 faces of these are somewhat swollen into a kind of bulb, which in alcohol 

 contracts into something the appearance of a disk. The third finger is 



