The Mountain Sucker 



cartilaginous sheath; eye small, behind middle of head, not high 

 up; suborbital bones small and narrow; opercle smooth and 

 narrow; isthmus moderate; gillrakers moderate, soft; pharyngeal 

 bones strong, the teeth rather wide apart, increasing in size 

 downward; scales about equal over the body, with wide, exposed 

 surfaces; lateral line nearly straight, well developed; fins rather 

 large, the dorsal beginning in front of ventrals and ending just 

 before anal, strongly falcate in front, the length of the first and 

 second developed rays more than half base of fin, the following 

 rays rapidly shortened to about the eighth, the remaining rays 

 all short; caudal fin large, widely forked, the lobes equal; anal 

 fin quite small, low and scaly at the base; pectoral long and 

 somewhat falcate; air-bladder in two parts, the anterior short, 

 the other long; sexual peculiarities marked, the males in spring 

 with black pigment and the head covered with small tubercles. 

 Colour very dark, the males in spring almost black. 



GENUS PANTOSTEUS COPE 

 The Mountain Suckers 



This genus resembles Catosiomus, from which it differs chiefly 

 in having the fontanelle nearly obliterated, and in having a more 

 or less developed cartilaginous sheath on each jaw. The species 

 are all western, chiefly in the Rocky Mountain region and west- 

 ward, mostly in rocky brooks in the arid districts. The 8 

 known species are each of rather small size, and scarcely valued 

 as food. 



Mountain Sucker 



Pmitosteus jordani Evermann 



Pantosteus ari:{once reaches a length of 9 inches, and is 

 known only from Salt River at Tempe, Arizona. T. generosus, 



45 



