Atherinoid Fishes from Mexia. 53 



diameter of eye, which is 4^ times in Icnj^th of heaJ and 

 equals width of inferorbital ron;ioii ; maxilhiry extcn linj^ to 

 below anterior border of eye or a little biiyond ; de[)th of sub- 

 orbital region barely \ the dianioter of the eye. 21 or 22 

 p;ill-rakers on lower part of anterior arch. Dorsals V-VI, 

 I 11-1^; longest spines not quite ^ length of head; the 

 distance between the two tins equals the base of tiie spinous 

 one. Anal I 20-22, originating under posterior extremity of 

 spinous dorsal. Pectoral acutely pointed, about § length of 

 head, contained O times in total length, extending to above 

 middle of ventral. Ventrals reaching vent. (Jaudal deeply 

 forked. Caudal i)eduncle twice as long as deep. iScales with 

 crenate edge, 52 to GO in a longitudinal series and 20 to 22 

 in a transverse series. A well-marked silvery lateral stripe. 

 Total length 200 millim. 



Several specimens from Lake Chapala, collected by 

 Dr. A. C. Duller. 



This species is very closely related to C estov, .lord., from 

 the same lake, and likewise known under the name of 

 Pescado bianco \ but it differs from Jordan's and Stein- 

 dachner's descriptions by the longer pectoral fin, the more 

 numerous anal rays, the narrower suborbital region, and the 

 smaller number of scales along the body. 



Chirostoma sphyrcena. 



Depth of body 6 times in total length, length of head 3|. 

 Head large, suggestive of a Sphyrcena, with the lower jaw 

 projecting; teeth in both jaws intermixed with large canines; 

 vomer toothless ; snout acutely pointed, 2^ diameter of eye, 

 which is 6^ times in length of head and equals | interorbital 

 width ; maxillary extending to below anterior border of eye ; 

 depth of suborbital region equalling the diameter of the eye. 

 23 gill-rakers on lower part of anterior arch. Dorsals V, 

 I 11; longest spines not quite ^ length of head ; the distance 

 between the two fins equals double the base of the spinous one. 

 Aral 121, originating a little behind posterior extremity of 

 spinous dorsal. Pectoral acutely pointed, nearly ^ length of 

 head, contained 5 times in total length, extending to above 

 middle of ventral. Ventrals not reaching vent. Caudal 

 deeply forked. Caudal peduncle twice as long as deep. 

 Scales with crenate edge, 65 in a longitudinal series and 20 

 in a transverse series. A well-marked silvery lateral stripe. 



Total length 225 millim. 



A single specimen from Lake Chapala, collected by 

 Dr. A. C. BuUer. 



