112 Field Columbian Museum — Zoology, Vol. 111. 



in the head; teeth on jaws small, in bands; scales 54 to 57-19: gill- 

 rakers 5-|-2o; base of anal fin i| in hand, its rays 20. ocOTLAN.t. 



mm. Scales in the lateral series 70, transverse 18; teeth on jaws 

 large and numerous, not arranged in definite rows, usually i to 3 

 large teeth on vomer; base of anal \\ in head, its rays 18 to 19. 



ESTOR. 



Chirostoma jordani Woolman. 



This is one of the smallest species of the genus. Its short 

 snout and very oblique mouth at once distinguishes it from all 

 other species. It is perhaps more proper to restrict the use of 

 Eslopsarum to this species only. Gill-rakers 4-I-14— 18: vertebra; 

 21-1-17 = 38; length of longest specimen, 2.75 inches. Chalco; 

 Texcoco. 



Chirostoma arge Jordan & Snyder. 



A small species so far found only m streams. Gill-rakers 

 3_|-ii — 14; vertebrae 184-18 = 36. Length of longest specimens, 

 2.75 inches. Aguas Calientes; Lagos. 



Chirostoma bartoni (Jordan & Evermann). 



Two specimens of this species from Lago de Lerma, near the 

 City of Lerma in the; State of Mexico, were presented to this 

 Museum by the United States National Museum. The scales of 

 one of these specimens has crenate edges and is very rough; on 

 the other specimen the scales are very smooth, as they are on the 

 type, which I have been permitted to examine. Scales slightly 

 more crowded on the nape than is usual in the more nearly 

 related species. Origin of dorsal fin slightly nearer tip of snout 

 than base of caudal fin. 



Chirostoma attenuatum, sp. nov. 



Type, No. 3631, F. C. ]\I. Length, 3.25 inches. 



Locality, Lago de Patzcuaro, Patzcuaro, Michoacan, Mexico. 



Head 4^: depth 5^^; D. v-9; A. 13; scales 42-11. Body rather 

 slender, not much compressed; caudal peduncle long and slender; 

 lower jaw slightly the longer; snout pointed, 3I in the head; 

 mandible 3; interorbital space 3; maxillary reaching vertical 

 from front of orbit; mouth small, oblique, but much less 

 so than in C. jordani. Teeth very small, numerous in both 

 jaws, those in the upper jaw mostly in two series; in a band 

 in lower jaw; scales large with entire edges, those on the nape 



