ICHTHYOLOGY. 



39 





Catal. 



No, 



Cor. No. 

 of teeth. 



No of 

 spec. 







166 

 167 



2736 



4 

 4 



List of specimens. 



Age. 



Locality. 



When col- 

 lected. 



Whence obtained. Nature of 



specimens 



Collected by 



Young. Rio Santa Cruz, or Sonoito 

 Adult.. Rio Sonoito 



1851 

 1851 



Col. J. D. Graham 



do 



Alcoholic John II . Clark. 



do 





1. ACOMUS LATIPINNIS, Grd. 



Plate XXIV, Figs. 1—6. 



Spec. Char. — General aspect sub-fusiform. Head proportionally small, and contained about five times and a-half in the total 

 length. Eyes small, situated near the upper surface of the head. Mouth small, also, the lips being large and fleshy. The fins 

 are all very much developed, constituting a prominent specific feature. Tho upper margin of the dorsal is slightly concave, 

 and the posterior margin of the caudal crescent-shaped ; the anal, ventrals, and pectorals being exteriorly rounded or lanceolated. 



Syn. — Catostomus lalipinnis, B & G., in Proc. Acad. Nat. Sc. Fhilad. VI, 1853, 388. 



Jlcomus latipinnis, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 173. 



The scales are of medium size, sub-elliptical, longer than deep, and considerably smaller on 

 the back than on the sides and on the abdomen. The lateral line runs along the middle of the 

 flanks from the opercle to the base of the caudal fin. 



D 1, 14 ; A 2, 8 ; C 5, 1, 8, 8, 1, 6 ; V 10 ; P 18. 



The upper part of the body is reddish brown ; the upper part of the tail and the flanks are 

 greenish brown ; the abdomen being yellowish orange. The caudal fin is olive; the anal, ven- 

 trals, and pectorals exhibit traces of deep orange, especially on their outer margin. 



Plate XXIV, fig. 1 represents Acomus latipinnis, somewhat reduced in size ; fig. 2 is the 

 head from beneath, to show the mouth and lips ; fig. 3, the head from above; fig. 4, a scale 

 from the dorsal region ; fig. 5, a scale from the lateral line ; and, fig. 6, a scale from the abdo- 

 minal region. 



List of specimens. 



Catal. 

 No. 



254 



255 



Cor. No. 

 of teeth 



No. of 

 spec. 



A are. 



2803 



Locality 



When col- 

 lected. 



2 



2 



Adult. 



Whence obtained. 



Nature of 

 specimens. 



Rio San Pedro, tributary 



of the Rio Gila. 

 do 



1851 



Col. J. D. Graham 



Alcoholic. 



1851 



do 



do 



Collected by 



John H. Clark- 



do 





2. ACOMUS GUZMANIENSIS, Grd. 



Plate XXIII, Figs. 6—10. 



Spec. Char — The head forms the fifth of the total length ; its shape is sub-quadrangular, sub-pyramidal. The eyes are 

 small and circular. The lips are well developed and covered with large papillae, but the posterior one is less indented than in 

 •ft . latipinnis . It has the general physiognomy of A. latipinnis, owing to the great development uf its fins. It is, however, 

 very readily distinguished from the latter by the presence of much larger scales, especially upon the dorsal region. In shape, 

 the scales are similar to those of A. latipinnis, being elliptical, somewhat longer than deep, but the radiating furrows are more 

 numerous. 



Syn.— Catostomus (Acomus) guzmaniensis, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 17a 





