XXXII. CHIROSTOMA 73 



The scales of this form, as indicated by Dr. Meek's description 

 and figure, are finer than in C. bartoni (= attenuatum), to which 

 species Mr. Regan wrongly referred zirahuen. 



In C. ZIRAHUEN the teeth are biserial or nearly so. Those of the 

 outer series of the mandible are enlarged, but still small. A similar rela- 

 tion holds true for the upper jaw laterally, but anteriorly the teeth of 

 both premaxillary series are about as large as those of the outer man- 

 dibular row. 



119. Chirostoma patzcuaro Meek, 1902.-^'- 



(Plate VII, Fig. 26) 



Chirostoma patzcuaro Meek, Publ. Field Mus., Zool, 3, 113, pi. 27, 1902; 5, 174, 



fig. 56, 1904; Regan, Biol. Centr.-Amer., Pisces, 58, pi. 10, fig. 1. 1907. 



Type-locality. — Lago de Patzcuaro, Mexico. 



Range. — Lake Patzcuaro, Patzcuaro, Mexico. 



The type figure of this species, and that of C. zirahuen, are poorly 

 drawn, showing the eye too large and the lower jaw too short. 



The teeth of C. patzcuaro are arranged in narrow bands. The 

 outermost teeth of the lower jaw, and the innermost of the anterior 

 teeth in the upper jaw, are enlarged, but not canine-like. 



Chirostoma patzcuaro differs from C. zirahuen in the more 

 compressed form, more numerous anal rays, the crenate scales, etc. 

 From C. humboldtianuai, with which it was taken in Lake Patzcuaro, 

 it differs in the smaller size attained, in the higher and more anteriorly 

 inserted first dorsal, and in dentition. It resembles humboldtianum 

 quite closely, however, like that species having the scale margins weakly 

 crenate. Dr. Meek in 1902 placed the two species in different subgenera, 

 and having overlooked their crenate scale margins, excluded both from 

 the subgenus Lethostole. 



120. Chirostoma humboldtianum (Cuvier and Valenciennes), 1835.-^*- 



(Plate VIII, Fig. 27) 

 Atherina humboldtiana Cuvier and Valenciennes, Hist. Nat. Poiss.. 10. 479, 

 pi. 306, 1835. 

 Atherinichthys humboldti Giinther, Catalogue Fishes Brit. Mus., 3, 404, 1861 



(altered spelling). 

 Chirostoma humboldtianum Jordan and Evermann, Bull. U. S. Nat. Mus., 47, 

 pt. 1, 793, 1896; pt. 3, 2839, 1898; pt. 4, 123, fig. 334, 1900; Evermann. Proc. 

 Biol. Soc. Wash., 12, 2, 1898; Jordan and Snyder, Bull. U. S. Fish Comm., 19, 

 134, 1899 (1900); Evermann and Goldsborough, ibid., 21, 152, 1901 (1902); 

 Meek, Publ. Field Mus. (Zool), 3, 114, 1902; 5, 175, 1904; Regan. Biol. 

 Centr.-Amer., Pisces, 60, 1908. 

 Type-locality. — Lake near City of Mexico. 

 Atherina vomerina Cuvier and Valenciennes, Hist. Nat. Poiss., 10, 481, 1835. 



Type-locality. — Lake near City of Mexico. 

 Range. — Lakes in the Valley of Mexico and the Lerma Basin, Mexico. 



