PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 301 



and with a slight symphysial knob as in Hyhognathus. Eye small, 

 nearly C in head. 



Scales rather small, 10-55-7 or 8, the lateral line complete, somewhat 

 deciirved. 



Dorsal fin moderate, slightly behind ventrals, D. 8 ; A. 7. Anal rather 

 high. 



Pectorals not reaching ventrals, the latter (not reaching) to vent. 



Teeth 4-4, not hooked, with broad grinding surface as in Hybognathiis. 



Color dark bluish above, scales everywhere with fine black punctula- 

 tions. Sides without black spots. A black spot at base of caudal &n. 



Peritoneum black; intestinal canal considerably elongate. 



Types, numerous examples (23130-23131), 5 to 7 inches in length, 

 taken by Professor Duges in Lake Tupataro in Guanajuato, Mexico. 

 The less number of scales (55 instead of 88) well distinguishes this 

 species from Z. siderium. 



Hudsonius altus Jordan, sp. nov. 



Allied to Hudsonius fluviatilis. 



Body moderately elongate, compressed, deep, the back somewhat ele- 

 vated, the depth 3f in length to base of caudal. 



Head short, somewhat depressed above, moderately pointed, 4| in 

 length to base of caudal. Eye moderate, shorter than snout, 5 to 6 in 

 length of head. Mouth medium, quite oblique, terminal, the premax- 

 illary on the level of the pupil, the maxillary not reaching the front of 

 the pupil. Jaws equal in the closed mouth. Preorbital large. 



Scales rather large, not closely imbricated, 8-46-4. Lateral line 

 strongly decurved, 19 scales in front of dorsal fin. 



Dorsal fin high, inserted over the base of the ventrals. Dorsal rays 

 I, 8. Anal I, 8. Caudal fin rather broad, forked, its peduncle deep and 

 compressed. 



Ventrals shortish, reaching vent. Pectorals falling just short of 

 ventrals. 



Teeth 4-4, hooked, with narrow grinding surface. 



Color bluish above, sides silvery, fins plain. 



Types, several specimens, numbered 23129, the largest about 8 inches 

 in length, obtained by Prof. A. Duges in Lake Tupataro in Guanajuato. 



This species differs from its northern relatives, fluviatilis^ storerianus, 

 etc., in the larger head, the oblique mouth, and in the presence of but 

 one row of teeth. 



United States IsTational Museum, 



Washington, December 18, 1879. 



