110 



BULLETIN 34, UNITED STATES NATIONAL MUSEUM. 



round tbeir inuer margins to a point just in advance of their anterior, 

 then turn abruptly inwards and slightly backwards, making a right 

 angle with their previous course. They converge, but do not unite. 



Tongue large ; as broad as long. Gular fold well marked ; parotoid 

 groove not visible, perhaps accidentally. It is difficult, as in the G. tene- 

 hrosus, to distinguish the costal folds. There are not more than twelve. 



The tail is short and stout; its ujiper edge is much compressed, as is 

 the posterior half; its glandular structures are much less developed 

 than in other species of Amblystoma, the crypts of the crest being 

 minute and globular. Length of tail equal from its origin (posterior 

 margin vent) to posterior outline of sternum. 



The extremities are very stout, just meeting when laid along the side. 

 The palms and soles are very wide, and the toes short and flattened. 

 Thej stand, as regards length, behind, 3, 4, 2, 5, 1 ; before, 3, 2, 4, 1. 



Fig. 23. Chondrotus aterrimus, No. 5242 ; natural size ; Kocky Mountains. 



The color is black above, lead colored below. 



Measurements. 



In. Lin. 



Length from snout to gape (flat ijrojection) 7. 1 



Length from snout to gular fokl 12. 75 



Length from snout to axilla 19. 1 



Length from snout to groin 39 



Length from snout to end of vent 48 



Length from snout to end of tail 6 6 



Width of head ." 9.75 



Width of tongue 5.2 



Width hetween eyes anteriorly 5 



Width hetween nostrils 4 



Width hetween inner nostrils 3 



Width from eye to nostril 2.25 



Circumference of helly 23. 6 



Greatest height of tail 5. 4 



Greatest width of tail 4.5 



Free portion of longest finger 2.5 



From elhow to tip of finger 9. 75 



Free part of longest toe 3 



Knee to tip of longest toe , 11 



Extent of Outstretched toes 6. 6 



No. 5242; one specimen; North Tiocky Mountains; Lieutenant Mullen. 



