1854.] 27 



12. Astyanax argeis-tatus, B. and G. Body very much compressed. Head 

 short, forming about the fifth of the entire length. Eyes lar^e and circular. 

 Mouth of medium size, its angles not extending to the vertical of the pupil. 

 Opercular apparatus quite narrow. Dorsal fin subquadrangular, higher tinm 

 long, slightly concave upon its upper margin, its origin being midway between 

 tip? of snout and base of caudal fin. Adipose slender, opposite the posterior 

 portion of anal. Caudal deeply forked and longer than the head. Anal very 

 long, exteriorly concave, much deeper anteriorly than posteriorly, and situated 

 behind the dorsal. Ventrals immediately under the dorsal, and rather slender. 

 Pectorals likewise slender, their tips, however, do not reach the base of ventrals. 



D I. 10. A I. 20+1. C 5. I. 9. 8. I. 4. V 8. P 13. 



Scales higher than long, somewhat truncated anteriorly ; their surface exhibit- 

 ing several very marked diverging striae. Lateral line conspicuous, slightly in- 

 clined downwards. 



Back deep reddish brown. Sides silvery. Belly reddish. Fins reddish yel- 

 low. An elongated black spot at the base of the tail, extending along the cen- 

 tral ray of caudal fin. 



Upper tributaries of Rio Nueces. J. H. Clark. 



CYPRINID^. 



13. Catostojius congestus, B. and G. At first sight this species calls to mind 

 C. gibhosus, by its short and contracted shape ; it differs from it, however, in 

 the scales and form of the fins. The head is contained five times and a half in 

 the total length. The snout is blunt, abruptly truncated, and the mouth very 

 small. The eyes are large, subelliptical, and their longitudinal diameter con- 

 tained four times in the length of the head from the tip of snout to posterior mar- 

 gin of opercular apparatus. The dorsal fin is subquadrangular, its anterior mar- 

 gin being nearer to the tip of snout than to the base of caudal. The caudal is 

 semilunar, with the lobes rounded. The anal is narrow, its length less than the 

 half its height. The ventrals are inserted under the middle of the dorsal. The 

 tip of pectorals does not reach the base of ventrals. 



D II. 12 ; A I. 7+1 ; C 4. 1. 8. 8. I. 3; V 9 ; P 17. 



The scales are large, there are fourteen rows across the line of greatest depth 

 of body. The lateral line, which runs straight along the middle of the side, 

 contains about forty-six scales. 



The color as preserved in alcohol is uniform reddish brown above, lighter be- 

 neath, sides silvery. The fins are all unicolored, and of the tint of the region 

 to which they belong. 



Rio Salado, Texas. John H. Clark. 



14. Catostomus clarkii, B. and G. A rather small and short species, in shape 

 subfusiform and compressed. The dorsal line is gently arched. Head small, 

 subcorneal, truncated anteriorly, forming a little less than the sixth of the total 

 length of tbu fish. The eyes are subcircular, of medium size, their diameter 

 being contained about four times in the length of side of head. The mouth is 

 larger than in C. covgextus, and surrounded with more developed lips. The up- 

 per margin of dorsal fin is slightly concave, its anterior margin as high as long. 

 The caudal is subcrescentric posteriorly, with rounded lobes. The insertion of 

 the anal is narrow, its height is twice and a half the width. The insertion of 

 ventrals is under the posterior third of the dorsal. The pectorals are elongated 

 and of medium development. 



D II. 114 1 ; A II. 7 ; C 5. I. 8. 8. I. 4 ; V 10 ; P 17. 



The scales are rather lame; about twenty rows across a line from base of ven- 

 trals to anterior margin of dorsal. Sixty-eight to seventy scales in the lateral 

 line, which extends to caudal fin. 



Colors in alcohol : greyish brown above, with scattered darker nebulous spots; 

 sides greyish; belly whitish ; fins unicolor, vertical ones greyish; horizontal 

 ones yellowish. 



Rio Santa Cruz, Gila. John H. Clark. 



