44 Field Columbian Museum — Zoology, Vol. V. 



tip of snout and base of caudal; base of dorsal 2-| in head; longest 

 dorsal ray i| in head; pectoral 1/-3 in head; ventral if in head; 

 caudal fin rather short, forked; caudal peduncle robust, its least 

 depth 2 1 3 in head; lateral line decurved anteriorly, complete; gill 

 rakers long, longest about 2 /$ diameter of eye, about 66 on first gill 

 arch; alimentary canal elongate, with about 5 convolutions; peri- 

 toneum black. 



Color light brownish, lighter below; no distinct lateral band; on 

 smaller specimens (less than 4 inches) a dark caudal spot; fins all 

 plain. Length about 12 inches. 



This species is so far known only from Lago de Chapala, where 

 it is quite abundant and is much used for food. Ovaries of females 

 taken the last week of May are quite mature. The spawning season 

 is probably in June. 



1 (>. Algansea Girard. 



Algansea Girard, Proc. Acad. Nat. Sci. Phila., 1856, 182. (Type, 

 Leuciscus tincella Cuv. & Val.) 



Body robust, not much compressed; mouth moderate, terminal, 

 oblique; no barbels; caudal peduncle strong; fins very small; eyes 

 small; scales small, 60 to no in the lateral series; gill rakers short, 

 from 15 to 23 on first gill arch; intestinal canal moderate, ^ to 2 

 times the length of the body, folded on the right side; peritoneum 

 black; teeth 4-4; vertebra? 20 + 17 = 37. 



KEY TO THE SPECIES OF ALGANSEA. 



a. Scales large, 57 to 70 in the lateral series. page 



b. Gill rakers short and blunt, 15 to 19. 

 c. Gill rakers 3 + 12; dorsal fin inserted over 



ventrals tincella 44 



cc. Gill rakers 44-15; dorsal fin inserted slightly 



before ventrals dugesi 45 



bb. Gill rakers long and slender, 22 or 23 on the 



first gill arch; scales 65 in the lateral series rubescens 46 



aa. Scales small, 85 to 95 in the lateral series lacustris 47 



36. Algansea tincella (Cuvier & Valenciennes). Juilis. 



Leuciscus tincella Cuvier & Valenciennes, Hist. Nat. Poiss., 323, 



1844; City of Mexico. 

 Algansea tincella Girard, Proc. Acad. Nat. Sci. Phila., 1856, 183; 



City of Mexico: Girard, Mex. Bd. Sur., 46, pi. xxvn, figs. 



1-4, 1858; City of Mexico: Woolman, Bull. U. S. FishComm., 



1894, 6t; Rio Lerma, Salamanca, Guanajuato: Jordan & 



