THE BATRACHIA OF NOKTH AMERICA. 93 



of the A. j.jeff'ersonianmn touch each other and even overlap a little. 

 Tiie median portion of tlie dental series nsnally exhibits a slight angu- 

 lation anteriorly, while that of the typical subspecies is straight; but 

 this character is iu some cases not retained. The color is generally 

 easily recognized : black with light lateral spots. It resembles in this 

 respect the Plethodon gliitmosus, and to a less degree the Amhlystoma 

 microstomum as pointed out by Hallowell, and the unwary observer 

 may easily confound it with oue or the other of these species. But 

 lateral spots appear in some specimens of the typical variety, and the 

 ground color varies, as has been already described. 



This form is altogether northern iu its distribution, being especially 

 abundant in Canada. 



Amhlystoma jeffersomanitrn platineum Cope. 



Check-list, p. 26; Boulenger, Cat. Batr. Grad. Brit. Miis., ed. ii, 1882, p. 

 47. 

 Ambhjstoma platineum, Cope, I. c.,p. 198; StraucL, Salam., p. 65. 



This is a very elougate form of the A. jeffersonianum. 



The head is oval and the muzzle rounded. The length of the fissure 

 of the eye equals the distance of the nostril from the same ; is but little 

 less than the distance between nares, and half or a little more of the 

 distance between the anterior canthus of the same. Inner and outer 

 nares the same distance apart. Greatest width of head 5.5 to six times 

 in length from end muzzle to groin, five sevenths length from chin to 

 gular fold. Canthus of mouth behind canthus of eye. A series of 

 pores along the superciliary, which pass round the orbit behind and 

 below ; a scattered longitudinal series on the parotoid region, and a 

 transverse aggregation of the same on each side below parotoid groove; 

 a single series of the same for a short distance inside the ramus of the 

 mandible. The parotoid region possesses a thin stratum of dermal 

 cryptte. 



Costal folds twelve. The anterior is a little distance behind the axilla. 

 Toes subcylindric, similar to those of the A. jeffersonianum-. in one 

 specimen (type) they are separated by nearly an intercostal s[)ace when 

 the limbs are pressed to the sides ; in another they meet. Tail rounded 

 above at base, finally much compressed, but not elevated; equal in one 

 specimen to body and head to middle of orbit, measured from posterior 

 extremit}^ of vent. In the type, however, it is much shorter, extending 

 from its basis only to the eighth costal fold (from groin), but I suspect 

 that this is abnormal. 



Color leaden ; in type paler below, with numerous indistinct whitish 

 blotches. Eyelids yellowish margined. Specimen 4G88 has the abdo 

 men darker and without spots. 



The narrower head and more elongate body will distinguish this 

 species from the typical A. jeffersonianum. It is readily distinguishable 



