HYNOBIIDAE. 505 



salient angles on a line with the centers of the choanae; the length 

 of the inner side of one of the angles equal to the interval between the 

 choanae; the length of the outer side equal to one third this interval. 

 Tongue circular, strong and fleshy, filling the floor of the mouth, the 

 surface finely and longitudinally plicate; two fairly deep sulci with a 

 general antero-posterior trend, their outline that of two laterally 

 directed obtuse angles, enclosing about one half the central area of the 

 tongue. The gular fold moderately developed. Body depressed; 

 distance from the snout to the gular fold contained nearly three times 

 in the distance from the latter to the cloaca; median dorsal groove, 

 markedly deepened over the pectoral and pelvic regions; thirteen 

 well developed costal folds, including the one flexed to enter the axilla 

 and the one reaching the groin ; the nine middle folds continued across 

 the abdomen. Vent (of male) three slits meeting in front, the medium 

 longitudinal and longest, the two others obliquely directed forwards, 

 forming an angle; the borders swollen. Limbs stout, when appressed 

 the digits overlap for about two millimeters. Digits well developed. 

 Tail a trifle longer than the distance from the gular fold to the cloaca, 

 strongly compressed, deepened and fleshy in the posterior half; not 

 keeled; the tip rounded. Skin smooth; numerous mucous glands 

 on snout, around nostrils and eyes, and on upper and lower lips; para- 

 toids distinct; an irregular horizontal groove from eye to gular fold, 

 joined by a short vertical one posterior to angle of mouth. Color in 

 spirits slate, a trifle paler beneath." Total length 161 mm., head 23 

 mm., body G9 mm., tail 69 mm. 



Remarks: Thompson says "the larvae possess stout claws." This 

 is not quite clear, because the type is the only specimen known. 

 Larvae of BatraeJmperus possess the peculiar foot coverings of the 

 adults, and as the same modification exists in Pachypalaminus, one 

 might expect its larvae likewise to resemble the adults in this respect. 



The relationships are clearly with Hynobius. Among the species 

 of that genus it most resembles H. vandenburghi of the same region in 

 Hondo. It may well be a very local aquatic modification of that form. 



It certainly has nothing to do with Batrachupcrus, in spite of the 

 similar modifications of the feet, which may be considered as parallel- 

 ism which have appeared independently in animals of common 

 ancestry. 



Dr. Van Denburgh has kindly examined the skull of Pachypalaminus 

 for me and sent me a sketch of it. I find that it differs from that of 

 Hynobius in having a large premaxillary fontanelle. 



