36 



UNITED STATES AND MEXICAN BOUNDAKY. 



List of specimens . 



Catal. No. of 



No. 



spec 



Locality 



When collected. 



162 

 lb3 



1 

 2 



Devil's river, Texas. . . 

 Live Oak creek, Texas 



1851 



1854 



"Whence obtained. 



Nature of 

 specimens. 



Col. J. D. Graham . 



Major Emory 



Alcoholic . 



do 



Collected by 



John H. Clark. . 

 A. H. Campbe 1. 



1. PTYCHOSTOMUS CONGESTUS, Grd. 



Plate XXI, Figs. 5—8. 



Spec. Char. — 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, sub-elliptical, and their longitudinal diameter contained four times in the length 

 of the head from the tip of snout to posterior margin of opercular apparatus. The dorsal fin is sub-quadrangular, its anterior 

 margin being nearer the tip of snout than the base of caudal. The caudal itself is semi-lunar, with its lobes rounded. The 

 anal is narrow ; its length is less than half its height. The ventrals are inserted under the middle of the dorsal. The tip of 

 the pectorals does not reach the base of the ventrals. 



Syn. — Catostomus congestus, B. & G. in Proc. Acad. Nat. Sc. Philad. VII, 1854, 27. 



Ptychostomus congestus, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 172. 



The scales are large ; there are fourteen rows across the line of the greatest depth of the body. 

 The lateral line, which runs straight along the middle of the side, contains about forty-six scales. 



D 2, 12 ; AHorS; C 4, 1, 8, 8, 1, 3 ; V 9 ; P 17, 



The color, as preserved in alcohol, is uniform reddish brown above, lighter beneath ; sides 

 silvery. The fins are unicolor, and of the tint of the region to which they belong. 



Plate XXI, fig. 5 represents Ptychostomus congestus, size of life; fig. 6 is a scale from the 

 dorsal region ; fig. 7, a scale from the lateral line ; and, fig. 8, a scale from the abdominal. 



region. 







List of specimens . 







Catal. 



No. 



Cor 'g No. 

 of teeth. 



No. of 

 spec. 



Locality. 



When collected. 



Whence obtained. 



Nature of 

 specimens. 



Collected by — 



171 



2760 1 2 





1851 P.^l T n HroKom 



Alcoholic. . 



John H. Clark... . 



* ■ a 



r^m w ^^ %^ 







± \J%J X 



*»-• %-* A* V • M^ * V^ A \M* Si IX t I i * 



2. PTYCHOSTOMUS ALBIDUS, Grd. 



Plate XIX, Figs. 5—8. 



The general physiognomy of this species reminds us of P. congestus, although the body is 

 more slender, the head more elongated, and the caudal fin more deeply furcated. The mouth 

 is a great deal larger ; whilst the scales, which are longer than deep, are smaller than in the 

 species just alluded to. The ventral fins are missing upon the specimens before us ; their 

 insertion alone could be observed. The anal is quite narrow and slender. The color is greyish 

 white above, and greyish silver beneath. 



Six.— Ptychostomus albidus, Grd. in Proc. Acad. N t. Sc. Philad. VIII, 1856, 172. 



Plate XIX, fig. 5 represents Ptychostomus albidus, size of life ; fig. 6 is a scale from the 

 dorsal region ; fig. 7, a scale from the lateral line; and, fig. 8, a scale from the abdominal region. 



