188 BULLETIN 34, UNITED STATES NATIONAL MUSEUM. 



The skin of the A. iecanus is smooth. There are tliirteen hiteral 

 folds between axilla aud groin, and a strong pectoro-gularfold. The lat- 

 ter rises on each side in front of the shoulder, aud then turns upwards 

 and forwards. It is soon changed into a narrow dermal ridge or rib, 

 which is first convex upwards and then convex downwards, and then 

 terminates in line with the eye a diameter of the latter behind it. 



The feet are short, and the digits are flattened and are obtuse at the 

 tips. The pollex is only free by a slight notch, aud the hallux by a 

 rather deeper one. The phalanges are: Anterior, 1-2-3-2; posterior, 

 1-2-3-3-2. The third and fifth anterior digits are equal, while the 

 posteriors run 1-2-5-3-1, beginning with the shortest. The third and 

 fourth are nearly equal. 



The tail is somewhat depressed at the base, and becomes round in sec- 

 tion to the end of the proximal two fifths. It then becomes gradually 

 more compressed, until it is quite flat for the distal third. 



2 



3 4 5 



Fig. 46, Autodax iecanus. No. 14596. Shasta County, California; \. 



The color is black, relieved by a yellowish-brown shade of the chin, 

 and of the palms and soles, aud half the inferior side of the forearm- 

 A liue of the same color passes from the nostril to the upper lip, and the 

 lower eyelid has the same color. The superior surfaces and sides of 

 the hoa I, body, and tail are dusted rather thickly with small subeqnal 

 bluish-white spots, much as are seen in Plethodon glutinosus. 



Measurements of No. 14,596. 



M. 



Lengtli from end. of muzzle to eud of tail 122 



Length from end of muzzle to end of vent 071 



Length from end. of muzzle to groin 059 



Lengtli from end of muzzle to axilla 023 



Length from end of muzzle to canthus oris 010 



Length of fore limb 015 



Length of hind, limb 017 



Length of hind foot 008 



Width between orbits (least) 003(i 



Width of head (greatest) Oil 



The typical adult specimen displays the anomaly of the suppression 

 of the fourth j^osterior digit of the left side. 



This salamander resembles the Plethodon glutinosus in various re- 

 spects, especially in coloration. It has, however, a compressed tail, like 

 the P. intermedhis, and short series of vomerine teeth. The recurved 

 commissure of the mouth gives it the smiling, expression characteristic 



