194 [September, 



There are yet other species which bear a striliing external resemblance to 

 Alburnus, or better AlLurnellus, but differing by an ensemble of characters, which 

 have led us to establish, under the name of 



ALBURNOPS, 



a genus to include them. They may be distinguished by their smaller mouth and 

 by a thickening of the snout, which slightly overlaps the lower jaw, contrary to 

 what is the case in Alburnus and Alburnellus. In that respect, Alburnops will 

 remind us some species of Ihjborhynchus. The eye is large ; a very narrow 

 isthmus separates the gill apertures beneath. The insertion of the ventrals 

 talies place under the anterior margin of the dorsal fin, which resembles that of 

 Alburnus and Alburnellus. 



In both of the latter genera, the ventrals are situated in advance of the dorsal. 

 The caudal is furcated. On the other hand, the anal has a narrower base than 

 in Alburnus and Alburfiellus ; the lateral line is nearly medial, instead of being 

 deflexed upon the abdomen. The scales are large and deciduous. The pharyn- 

 geal bones resemble, by their configuration, those of Alburnellus. The teeth 

 themselves, are of the prehensile kind of the hooked type, with a narrow and 

 sometimes contorted grinding surface. They are disposed upon a double row of 

 two and four : 2 | 4-4 | 2, or 1 | 44 | 2. 



Thus we see that a marked difference between Alburnops and Alburnus s. Al- 

 burnellus, consists in the presence of a grinding surface in the former, and which 

 is absent in the latter. 



1. Alburnops elennius. This species has the snout most prominently 

 rounded. The posterior extremity of the maxillary extends to a vertical line 

 drawn across the anterior rim of the orbit. The eye is smaller than in the two 

 following species. The greatest length being about three inches and a half, the 

 head forming the fifth part of it ; the depth is less than the length of the 

 head. Theie are ten longitudinal rows of scales upon the greatest depth, six 

 above the lateral line and three below it. The color is reddish brown ; the 

 middle of the flanks, silvery ; the fins unicolor. 



Specimens collected iu the Arkansas river, near Fort Smith, by Dr. Geo. G. 

 Shumard. 



2. Alburnops suumardi. The snout is more conical than in the preceding 

 species, the mouth larger and more deeply cleft. The head constitutes, likewise, 

 the fifth of the total length, which measures three inches and a half. There are 

 but nine rows of scales, five above and three below the lateral line. Color red- 

 dish brown ; flanks silvery. 



Collected by Dr. Geo. C. Shumard, in the Arkansas river, near Fort Smith. 



3. Alburnops illecebrosus. Perhaps the most graceful of the three species 

 so far known of this genus. The number of rows of scales is ten, as in A. 

 blennius. The snout less prominent than in A. slnmiardi, and more so than in 

 A. blennius. The eyes are the largest in the genus. The head is contained five 

 times and a half in the total length, which averages about three inches. Color 

 reddish brown ; flanks silvery. 



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



Under the name of 



CODOMA, 



we arrange small cyprinoids, characterized by a short head and rounded snout, 

 terminated by a small mouth, the cleft of which does not reach a vertical line 

 drawn in front of the orbit; there being no barbels at its angle, and both jaws 

 even. The isthmus is of moderate width. The body is more or less elongated, 

 compressed. The insertion of the ventrals is situated in advance of the anterior 

 margin of the dorsal. The caudal is bifurcated, and like the rest of the fins, rather 



