Jordan and Evermann. Fishes of North America. 2049 



in a tube; lower jaw projecting beyond upper, turned upward at tip, a 

 long barbel at the symphysis; teeth on jaws and vomer, a single row on 

 pa I iitines ; gill membranes free from isthmus, united ; both dorsals present ; 

 ventrals very short ; plates of body slightly keeled, without spines ; verte- 

 bra' about 45. (Named for Petrus Simon Pallas, naturalist and explorer, 

 tbe accomplished author of Zoographia Rosso- Asiatica, 1811.) 



a. Three plates in front of ventrals; barbel long. BARBATA, 2406. 



aa. Two plates in front of ventrals ; barbel short. AIX, 2407. 



2406. PALLASIXA BAKBATA (Steindachner). 



Br. 5; D. VI to IX, 7; A. 9 to 12; P. 12; V.3(I,2); C. 11; lateral line 45 

 or 46 ; vertebrae 15 -f- 30 = 45. Pyloric caeca 6 (1 individual). Body slightly 

 depressed in front, depth at base of pectorals f or y of width, slender, 

 width about 11 in length. Ridges of the dorso and ventro lateral series 

 strong, the dorsal and lateral halves of the plates form a right angle; no 

 ridge on the inferior lateral row and the plates of the superior lateral row 

 absent anteriorly, so that the body is 4-hedral in front of first dorsal, with 

 dorsal and ventral faces flat or a little concave and the lateral convex. 

 Under first dorsal, the superior lateral series begins with keeled plates, the 

 ridge of the inferior lateral series becoming more prominent, so that under 

 the dorsals the body is 8-hedral; dorsal and ventral faces grooved, and 

 depth equaling length. Caudal peduncle strongly depressed, nearly 

 4-hedral (median dorsal and ventral ridges extremely low) ; 45 or 46 plates 

 in the dorsal series, 4 pairs between dorsals, 12 to 13 pairs from ventrals 

 to anal, 5 to 9 pairs between last ray of second dorsal and first median 

 ventral plate ; 3 or 4 large plates in a median longitudinal row on breast, 

 with about 1 row of 4 or 5 small ones between it and the series forming 

 the edge of breast; plates radially striated and a little elevated at the 

 center; none between ventrals and vent. Membrane behind vent without 

 plates (or as many as 19, Steindachner's excellent figure). Branchiostegal 

 membrane naked posteriorly, 2 or 3 plates auterolaterally. Narrow nude 

 surface of lower jaw with a series of several plates; 2 or 3 plates in front 

 of pectoral. Head very long and narrow, gently tapering, nearly as high 

 as wide. Orbits nearly circular, the longitudinal diameter about 5 in 

 head and 2 in snout. Interorbital space moderately concave, nearly 2 in 

 orbit. Supraocular ridges moderate, occipital ridges scarcely defined, 

 temporal ridges moderate, all spineless ; no suborbital ridge ; suborbital 

 bone spineless ; a sharp spine at posterior angle of preopercle and 2 smaller 

 flat ones below this ; a longitudinal series of 4 or 5 poorly developed plates 

 on lower part of cheek, between the long horizontal limb of preopercle 

 and orbit. Snout long, tubular, about 2| in head. Frontal bones much 

 elongated forward, an additional bony plate in front of preorbital and over- 

 hanging the maxillary; several small plates in membranaceous interval 

 between preorbital and frontal in front of orbit. Posterior inferior 

 angle of maxillary produced backward, reaching a little more than half- 

 way to orbit. Median rostral plate absent. Lower jaw long, curved 

 upward in front, projecting beyond the upper and entering profile; mouth 

 oblique. Teeth in narrow bands on jaws and vomer, about 1 row 011 pal- 



