68 



BULLETIN OF THE BUREAU OF FISHERIES. 



The gillrakers are short and stubby; 6 or 7 small protuberances. The body is deep and robust; 

 no more so, however, than many examples from the Columbia or Bonneville systems. The lateral 

 line sometimes extends to the last scale, although in most cases it is less complete. It often differs 

 on opposite sides of the body, and sometimes it extends the entire length, but interrupted at irregular 

 intervals. It is found to end anterior to the dorsal or at any point between the dorsal and caudal fins. 



Lateral line 



Specimens from — 



Susan Creek 



Carson River 



Fallen Leaf Creek 



Humboldt River Palisade 



Star Creek 



Marys Creek 



Quinn River 



Almost 

 complete. 



Ends 



before 



anal fin. 



Ends 



near 



middle 



of anal. 



Ends 

 anterior 

 to dorsal. 



3 



14 



No scattered brown scales occur, their absence, however, not being characteristic of Lahontan spec- 

 imens alone. The dorsal is almost always inserted well behind the ventrals, nevertheless the distance 

 is found to vary from a point near a vertical through the insertion of ventrals to almost halfway between 

 their bases and the anal opening. The pectorals are usually short, not reaching the ventrals. Speci- 

 mens with longer fins are easily foimd, the pectorals at times extending well beyond the bases of ventrals. 

 Usually there are not less than eight fully developed rays in the ventral fin. When depressed their tips 

 fall short of the anal opening or extend even to the origin of the anal fin. The edges of the fins are trun- 

 cate or rounded, never falcate. Membranous stays do not appear behind the bases of the ventrals. 

 Rudimentary caudal rays number from three to six. A more or less definite, broad, dark, lateral stripe 

 is present, although in some cases it is poorly defined and seen only on the caudal peduncle. Usually 

 a distinct narrow stripe appears along the side of the abdomen. Dark blotches of variable size are 

 often present, but the dark pigment is not confined to particular scales. Examples from the desert are 

 lighter than those from wooded areas, the stripe being present on individuals from both regions. This 

 stripe is not black and sharply defined as in specimens of A . nubila from the coast region of Oregon and 

 Washington. The bright silvery area observed by Rutter soon disappears under the action of preserv- 

 atives. 



In life the color is yellowish olive above, growing brassy on the sides and yellowish beneath. 

 The spots and stripe are olive black. End of maxillary and small space behind it, a spot posterior to 

 edge of opercle, median area of throat and breast, a broad axillary area of both pectorals and ventrals, 

 and a narrow space along base of anal, bright crimson with a slight brassy reflection. Fins tipped with 

 yellowish red. 



The teeth in 10 examples were 4, i-i, 4, strongly hooked, and without grinding surface. 



The alimentary canal is not longer than the entire length of the individual. The peritoneum is 

 jet black, occasionally lighter. The bladder extends over about four-fifths of the visceral cavity. A 

 female caught at Tahoe City June 27 was full of nearly ripe eggs. 



The scales are very small, convex, rounded in outline, and possess both basal and apical radii. 

 They are almost if not altogether indistinguishable from those of Hesperoleucus mitrulus, thus rendering 

 their minute structure useless as a generic character. 



This species inhabits both streams and lakes. In the rivers it is most often taken on the ripples. 

 In lakes it frequents the shallow water, swimming near the bottom, or in crevices between rocks. From 

 above, when seen in the water, the color is decidedly black. In the lakes it was taken with hook and 

 line, a method which will often secure very small fishes where the net fails on account of deep, clear 

 water or rough bottom. 



Agosia nevadensis and A. velifer are very distinct from this form and are easily recognized. 



