102 PROCEEDINGS OF THE ACADEMY OP 



the orbits. The fins are yellowish, unicolor, except the first dorsal, which is 

 margined with black. During life we imagine this fish to be one of the prettiest 

 inhabitants of the fresh waters of this continent. 



XXXII. To such species of the genus Utheostoma, in which the two dorsal 

 fins are united, Rafinesque proposes to apply the name of Aplesion, as alluded to 

 above. A species of the latter genus was collected with the preceding one by 

 Mr. John Potts, in Chihuahua river and tributaries. Its body is rather short 

 and deep, proportionally deeper than in the other genera of the family. The 

 dorsal region is regularly convex from the occiput to the peduncle of the tail. 

 The caudal fin is rounded off and fan-shaped. The spinous portion of the 

 dorsal fin is nearly of the same height as the soft portion, but much longer and 

 superiorly convex. The anal fin is smaller than the second dorsal. The ven- 

 trals are sublanceolated and the pectorals subelliptical in shape, rather small 

 or moderate in development, the tip of the ventrals projecting somewhat fureher 

 back than that of the pectorals, although not reaching the vent. The formula 

 of the fins is as follows : D x, 1, 10 ; A n, 7 : C 4, 1, 6, 6, 1, 3 ; V i, 5 ; P 1 1. 

 The head, which forms about the fourth of the total length, is rounded upon 

 the snout ; the jaws being nearly equal, the gape of the mouth somewhat 

 oblique, the posterior extremity of the maxillar bone extending to a vertical 

 line which would intersect the pupil. The eye is circular ; its diameter enter- 

 ing four times in the length of the side of the head, less than once in advance 

 of its anterior rim. The opercular apparatus, cheeks and throat are bare. The 

 scales are of moderate development deeper than long, very finely pectinated 

 posteriorly, where rounded off, and provided with radiating furrows upon their 

 anterior section. The color is of a uniform olivaceous brown tint, the dorsal 

 fin rather darker than the rest. We propose to call this species Aplesion potsii, 

 in remembrance of our esteemed friend from Chihuahua. 



XXXIII. A species of Oligocephalus, closely allied to 0. lepidus was collected 

 in Devil's river, Texas, by John H. Clark, under Col. J. D. Graham. It maybe 

 distinguished from its congener just alluded to by a much larger anterior dorsal. 

 The latter is nearly as high as the second dorsal and somewhat longer upon its 

 base. The body is rather short and quite compressed ; about two inches in 

 total length, in which the head enters four times and a half. The tips of the 

 ventrals are nearly even with those of the pectorals. The rays of the fins are : 

 D ix ; 13 ; A n, 8 ; C 4, 1, 7, 6, 1, 3 ; V i, 5 ; P 12. The scales are propor- 

 tionally well developed ; the nape is bare. The groundcolor is yellowish brown, 

 with blackish brown blotches more distinct along the dorsal line than on the 

 flanks. The second dorsal and caudal are transversely barred. The species 

 we will record under the name of Oligocephalus grahami. 



XXXIV. Another species still, of the same genus Oligocephalus ,was collected 

 in the Rio Leona, Texas, by the same party that secured the preceding one. 

 We will designate it under the appellation of 0. leonensis. It is a more slender 

 fish than either 0. lepidus or 0. grahami, although not quite so elongated as 0. 

 linslii. The largest specimens observed measure about two inches in total length, 

 in which the head enters four times and a half. The anterior dorsal fin is 

 longer but somewhat lower than the second dorsal, and superiorly convex. The 

 anal is well developed. The ventrals are small and spear-shaped, as well as 

 the pectorals when in a semi-closed condition. The tips of the latter extend 

 beyond those of the former, although very far from reaching the vent. The 

 formula of the fins is as follows : D ix ; 10 ; A n, 7 ; C 6, 1, 6, 6, 1, 5 ; V I, 5 ; 

 P 12. The ground color is yellowish olive, maculated with black or brown. 

 Second dorsal fin and caudal transversally barred. 



XXXV. We have bestowed the name of Oligocephalus pulchellus upon a species 

 collected in a tributary of Gypsum creek, which empties itself into the Cana- 

 dian river, by the party under Lieut A. W. Whipple, while exploring the R. R. 

 route along the 35th parallel. The only specimen preserved measures an inch 



[March, 



