n8 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. III. 



in different species of Chirostoma taken the last week in May. 

 Balsas. 



MUGILlDyE. 

 Agonostomus nasutus Gunther. 



The lips of some of the specimens from the Balsas are much 

 thinner than in the one large (6 inches in length) specimen from 

 Cuicatlan. Specimens from Balsas 3.75 inches in length, head 

 3|. Balsas; Puente de Ixtla; Cuicatlan. 



Mugil trichodon Poey. 



A few small specimens from La Antigua. 



CEXTRARCHID^. 

 Lepomis occidentalis, sp. nov. 



Type, No. 3660, F. C. M. Length, 4.75 inches. 



Locality, Rio Conchos, Jimenez, Chihuahua, Mexico. 



Head a: depth 2; D. x-n; A. iii, 9; scales 7-37-14. Body 

 oval, compressed, dorsal outline more arched than the ven- 

 tral. In smaller examples the profile is nearly straight or 

 slightly convex. In large examples (about 5 inches in length) 

 the profile is concave, with a prominent angle at the nape: mouth 

 moderate, the tip of the maxillary reaching vertical from pupil, 

 its length 3 in head; lower jaw slightly the longer; eye small, 4! 

 in head and 1 1 in the interorbital space; fins rather low. 4th dorsal 

 spine 3^ in head: pectoral short and rounded, its length \\ in 

 head; ventrals slightly longer than the pectoral, their tips almost 

 reaching anal: operculum with a well developed membranous 

 appendage or flap, this being largest in the larger specimens. 

 This flap has a narrow pale border. The caudal fin is very short, 

 its lobes rounded and of equal size, its length i^ in head. Teeth 

 on vomer, none on palatines; no supplemental maxillary. Gill- 

 rakers short, blunt, S on lower part of gill-arch. 



Dark olivaceous above, lighter below, each scale with a light 

 margin forming longitudinal lines along the rows of scales. These 

 lines are quite prominent on the lower half of the body. Xo 

 black markings on the fins; no blue lines on the cheeks, a few 

 dusky brown lines being present. Length about 6 inches. 



This species resembles Lcpomis megalotis; it differs from that 

 species in having a more robust body, smaller eye, a much shorter 

 pectoral fin, a much duller coloration and the absence of bright 

 blue stripes on the cheeks. It differs from L. haplognathus in 



