1856.] 191 



noids cannot yet be attempted with any sort of satisfaction, as long so the 

 eastern representatives are not all revised. 



The most curious genus, it must be conceded, is that of 



ExoGLOSSUM, Rafin. 



The body is elongated, subcylindrical, slightly compressed. The head is sub- 

 conical, flattened upon the occiput, and terminated by a blunt snout. The 

 mouth is subterminal, opening downwards and forwards, the lower jaw being 

 shorter than the upper and not surrounded by the lips around its symphysis, 

 the lips being largely developed at the angle of the mouth and along the upper 

 jaw also. The eye is of moderate size. The isthmus is wide. The origin of 

 the ventrals is situated opposite the anterior margin of the dorsal. The caudal 

 is bifurcated. The scales are of medium size, nearly quadrilateral. The pharyn- 

 geal bones are exiguous, very slender upon their inferior branch, hardly dilated 

 above. The teeth are of the raptatorial kind of the hooked type, without grind- 

 ing surface, instead of which a sharp, but not crenated, edge. They are dis- 

 posed vipon a double row of one and four, thus : 1 | 4 4 | 1. 



1. ExoGLoasuM MAXiLLiNGUA, Hald. in Rtipp, Hist, of Lane. Co., Pa., 1844, 474. 

 Agass. Amer. Journ. of Sc. 2d Ser. xix. 1855, 215. Cyprinus maxillingua, Lesu., 

 Journ. Acad. Nat. Sc. Philada. i. 1817, 85. Exoglossum Icsucurianum, Rafin., 

 Journ. Acad. Nat. Sc. Philada. i. 1818, 420. 



Prof. Haldeman was the first who thought of restoring the name of maxillingua 

 to this species. 



2. Exoglossum mirabile. A very characteristic species, very slender and 

 fusiform, and distinguished from the preceding by a smaller head, smaller 

 mouth, the position a little more backwards of the ventrals, and larger scales. 

 The color is reddish brown above, light reddish beneath, with a silvery band 

 along the middle of the flanks from head to tail. A black spot upon the inser- 

 tion of the caudal fin. 



Caught in the Arkansas River, near Fort Smith, by Dr. Geo. G. Shumard. 



Along with young specimens of Gila grahami, caught in the San Pedro, were 

 numerous little fishes from two and a half inches to three inches long, which, 

 upon a superficial examination, might not have been distinguished from their 

 associates just mentioned, for the fact of the absence of scales could not have 

 given them an aspect very different from the young Gil^e, since the latter have 

 very minute scales in their immature state. A careful comparison between the 

 two sets of specimens very soon revealed generic characters so peculiar, that we 

 had to institute, under the name of 



MEDA, 



a genus widely different from all other American cyprinoids, by the presence, 

 upon the anterior margin of the dorsal, of a stout undivided (though articulated) 

 ray, resembliog in its general appearance that which is observed in Barbus, Lu- 

 cioharbus, Scaphiodon and Systomus, differing, however, from all of these in the 

 structure of its posterior edge, which is grooved instead of being serrated. The 

 absence of buccal barbels in 3lda, is another feature to warrant its claims as 

 a genus, which differs from Cyprinus^ Carassius, Carpio, &c., by characters equally 

 obvious, as will be seen by the following diagnosis : 



Body elongated, slender, compressed, fusiform in its profile, and perfectly 

 naked. The lateral line may be traced along the middle of the flanks, slightly 

 deflexed upon the abdomen. The head is elongated, subconical, rounded upon 

 the snout without being truncated. The mouth is proportionally large, subter- 

 minal, its cleft slightly oblique upwards, the lower jaw fitting into the upper. 

 No barbels. The eye large and circular. The isthmus narrow. Dorsal fin 

 higher than long, provided anteriorly with a stout, articulated but simple and 

 osseous ray grooved posteriorly and nearly as high as the second ray, which ia 



