252 CALIFORNIA ACADEMY OF SCIENCES. 



cc. Suoiit long, slender, triangular. Body much elongate. Teeth in 

 the jaws none. Barbels united bj' a broad thin membrane; max- 

 illary barbel longest, reaching uearlj' to the base of the pectoral, 

 with several accessory barblets. Outer mandibular}' barbel split to 

 near its base. Eye 2| in the snout, 5 in the head. Lateral shields 

 high, covering two-thirds of the side of the body, with a marginal 

 series of spines. Humeral process scarcelj' longer than high. Dor- 

 sal spine shorter than the head, slightly serrate along both edges. 

 Head 4; depth 7-8; D. I, 6; A. 16; P. I, 10; V. 7; Lat. 1. 42. (Giin- 

 ther.) acipenseriniis 194. 



bh. Fontanel continued as a groove to tip of dorsal plate. 



h. Back, between the dorsal and adipose fins, and sometimes the belly 

 between the ventrals and the anal, with a series of plates. 



stenopeltis 195. 

 hh. Back, between the dorsal and adipose fins, naked. 



i. No teeth in the jaws; maxillary barbel reaching to edge of oper- 

 cle. Head compressed, snout conical, elongate. Eye 4|-5 in the 

 head. Snout in front of the nostrils, and the sides of the head, 

 naked. Humeral process about twice as long as high, ending in 

 a point somewhat behind the middle of the pectoral spine. Pec- 

 toral spine reaching a little beyond the base of the ventrals. 

 Lateral plates low. HeadS-S^; depth 5i-5i; D. I, 6; A. II; Lat. 1. 

 3 + 29-30. (Steindachner.) stahelul^. 



a. Minute groups of teeth in one or both jaws. 

 j. Maxillary barbel reaching beyond the head; head long, com- 

 pressed, with a long narrow snout, somewhat roof-shaped in. 

 the nuchal region. Lateral scutes serrate on their posterior 

 margins. Anterior nostril midway between tip of snout and 

 eye. Intermaxillaries each with a minute patch of teeth; some- 

 what larger patches in the lower jaw. Snout and cheeks covered 

 with skin. Humeral process extending beyond the middle of 

 the pectoral sijine. Pectoral pore large. Dorsal and pectoral 

 spines equal in length, serrate on both margins; the pectoral 

 extends beyond the base of the ventral fins. Head 3J; depth 

 5; D. I, 6; A. 14; P. I, 9; V. 7; Lat. 1. 34. (Steindachner.) 



morei 197. 



jj. Maxillary barbel extending to below the eye; bases of all the 



barbels united. D. I, 6; A. 12-13; P. I, 8-9; V. 7. Lat. 1. 32-35. 



Jc. Upper and lower profile of the snout equallj' oblique. (Kner.) 



hunieralis 198. 

 kk. Snout elongate, pointed; lower profile straight, the upper 

 descending. carinatus 199. 



aa. Shields on the anterior half of the body rudimentary or none; a sub- 

 dermal stay connects the dorsal plate with the tip of the humeral pro- 

 cess, a similar one connects the tip of the dorsal plate with the post 



