THE liATKAClIIA OF NORTH AMERICA. 95 



AMBLYSTOMA MACRODACTYLUM Buird. 



(Plate 25, tig. 6.) 



Baird, Joam. Ac. Phila. (2) i, p. 292, and U. S. Expl. Expedition, xii, part 2, 

 PI. ;U, iig. 3; Cop«, Proc. Ac. Phila., 1867, p. 198; Strauch, Salam., 

 p. 05 ; Boulengur, Cat. Batr. Grad. Brit. Mas., ed. ii, 1882, p. 48. 



This species is the sleuderest of all oiir species of Amhlystoma; iii 

 tills respect, as well as length of digits, exceediug the typical A.jeffer- 

 sonianum, but resembling the A.j. platineuiu. 



The head is rather large, depressed, and elongated, with a moderate 

 coustriction at the neck. The eyes are prominent, and distant less than 

 two lengths of the orbit. The outer and inner nostrils are each about 

 one orbit distant. The width of the head is about three-quarters the 

 distance to gular fold. 



The tongue is oval and longitudinal. The palatine teeth are in three 

 or four patches, the central largest, occasionally separated by an in- 

 terval less than half the diameter of the inner nostrils. Together they 

 form a line slightly angular anteriorly where they reach to about op- 

 posite the center of the inner nostrils; laterally they pass a little the 

 outer margin of the inner nostrils. 



The body is cylindrical, depressed, with twelve costal furrows. The 

 tail is long and is compressed for its distal half. The digits are longer 

 than in any other species of the genus, the interior being well develoj)ed 

 on both extremities. On the forefoot it equals the external toe in length, 

 while on the hind limb it is a little shorter than the fifth. The pha- 

 langes are : In front, 2, 2, 3, 2; behind, 2, 2, 3, 4, 2. 



The color in alcohol is leaden brown, witli a well-defined broad dorsal 

 stripe of grayish-brown, which, involving the whole upper surface of 

 the head and neck, contracts on the nape, swelling again on the back, 

 with an average breadth of the outer orbital space. This stripe extends 

 to the end of the tail. On each side of this dorsal stripe is a suffusion 

 of dark brown, which gradually pales through the color of the sides 

 onto the belly. There are also a few spots of the same in the dorsal 

 stripe. There are a few grayish-white dots scattered along the sides, 

 and perhaps on the limbs. 



Two specimens (4054) from Puget Sound agree in form with the 

 preceding specimen, the two central patches of palatine teeth perhaps 

 a little more angularly arranged. Instead of the grayish dorsal stripe, 

 however, there is a brownish-red one, and the sides are of a darker and 

 more continuous brown. No. 4711 has a similar character of palatines, 

 but a coloration more like the type. The palatines, in fact, extend a 

 little in front of the anterior border of the inner nostrils. 



Proportional dimensions. 



Spec. No. 4042, (type). 

 Bead : 



Length of gape of mouth to its width two-thirds. 



Width to distance from snout to gnlar fold .............. about three-quarters. 



Width to distance from snout to groiu ,..,... , .--- r 5 times, 



