5 BERTRAM G. SMITH. 



greater number of specimens captured by me were much smaller 

 than the extreme size given ; specimens of about 35-40 cm. were 

 apparently most numerous. The smallest sexually mature males 

 measured about 33 cm. ; females 35 cm. 



Form. — The general form of the body (see Fig. 2) is such as 

 to adapt it to bottom life, and to shallow crevices under rocks. 

 The flattened head is wedge-shaped in a horizontal plane, en- 

 abling the animal to force itself into very shallow crevices. The 

 fore limbs are adapted for ordinary locomotion, for climbing over 

 rocks, and for use to a slight extent in burrowing. 



As compared with the young, the adult is distinguished by the 

 general looseness and wrinkling of the skin at the sides of the 

 body, forming folds which become more prominent in adult life, 

 and by the flaps of skin on the posterior sides of the limbs. Dur- 

 ing locomotion these folds and flaps undulate in the water, con- 

 tributing to the uncouth appearance of the animal ; they hang 

 limp when the living specimen is taken out of the water, but be- 

 come stiffened in preserved specimens. 



Coloration. — Young adults vary but little in color or color 

 pattern. The ground color is a dull brown, with conspicuous 

 black spots and less conspicuous yellow spots, irregular in form 

 and distribution, scattered over the dorsal and lateral surfaces. 

 Since the coloration of the young adult is practically the same 

 as that of immature specimens from 16 cm. upward, Fig. 14, from 

 a specimen 26 cm. long, will serve to represent this stage, in 

 which the spots are more conspicuous than in the young larvae 

 or the more mature adults. In older specimens (see Figs. 2-4) 

 the general color effect may vary in two ways : it may become 

 either greenish brown, or decidedly reddish brown. As stated 

 by Reese ('05), these variations in color occur in both sexes. 



The coloration of the dorsal surface is protective, closely re- 

 sembling the gravelly bottom on which CryptobrancJms lives. 

 The spots contribute largely to this general effect. When the 

 stone under which a hellbender lies is overturned, the animal 

 sometimes remains perfectly motionless, as if instinctively rely- 

 ing upon its coloration for protection. On account of its size, 

 and the possession of various means of defense, it is probable 

 that Crypotobranchus has few enemies, and its coloration is of 



