180 [September, 



ance, covered with scales a little larger than ia //. puniceus but smaller than in 

 the other species of the same genus. The opercular apparatus is likewise well 

 developed. Color light red above, yellowish beneath ; a black spot upon the 

 anterior margin of the dorsal. 



From Hurrah creek, a tributary of the Rio Pecos ; collected by H. B. M611- 

 hausen, under Lt. Whipple. 



A very remarkable genus, inhabiting our western waters, is that of 



PiMEPHALES, Rafin. 



Its body is subfusiform when seen in profile, compressed, however, as usually. 

 The head is large, short, and very blunt upon the snout. The mouth being 

 small, slightly arched, and terminal ; both jaws even. The eye is of moderate 

 development. The isthmus is proportionalh^ wide. The dorsal fin is a little higher 

 than long, provided anteriorly with a rather thick and undivided, short and hard 

 ray. The origin of the ventrals takes place either immediately opposite the 

 anterior margin of the dorsal, or else a little posterior to it. The scales are 

 rather large and the lateral line, after a slight deflection along the thorax, fol- 

 lows the middle of the flanks to the base of the caudal fin. The pharyngeal 

 bones are of moderate stoutness, gently arched, the upper and lower limb nearly 

 equal though the upper is more curved ; the convex portion is regularly dilated 

 or expanded. The teeth are of the cultriform kind of the grinding type, very 

 slightly hooked, compressed, with a narrow grinding surface, disposed upon one 

 single row of four : 4 4. 



1. PiMEPHALES MACULOSUS. It Is a stouter fish than P. promelas, both in 

 body and head. The latter is almost round. The anterior margin of the 

 dorsal is equidistant between the extremity of the snout and the last scales upon 

 the caudal fin. The origin of the ventrals is situated a little posterior to the 

 anterior margin of the dorsal. The scales are larger also than in P. prornelas. 

 Upon a yellowish brown ground there are large and iri-egular black blotches 

 covering more than half the entire surface of the body. The fins are yellow 

 upon their bases and tips, and black upon their middle. The external margin of 

 the ventrals and pectorals is pure white. 



Caught in the sluice of the Ai'kausas near Fort ilakee, and brought home by 

 Lt. E. G. Beckwith, U. S. A. 



2. PiMEPHALES FASCIATUS. This spccics has the general aspect of /*. manilosus, 

 differing, however, from it by the position of the ventrals, which are inserted 

 under the anterior margin of the dorsal fin. The scales are smaller also. The 

 color is alternately brown and black in transverse fasciae. Dorsal fin provided 

 with two black spots, one anteriorly, the other posteriorly. The other fins being 

 unicolor, with the exception of the pectorals, which are greyish upon their ex- 

 ternal margin. 



From the Yellowstone river ; collected by Dr. F. V. Hayden. 

 Two immature specimens of this, or a similar species, were collected in Milk 

 river. Upper Missouri, by Dr. Geo. Suckley. 



"We separate from both Pimephales and Hyhorhynckus^ under the name of 



ALGOMA, 



some small fishes, partaking in a measure of the characters of the genera just 

 mentioned. The teeth are of the cultriform kind, of the grinding type, disposed 

 upon a single row of four : 4 4. The grinding surface is nearly linear, in which 

 respect the teeth resemble more those of Pimephales than of Hyborhynchus. The 

 pharyngeal bones do not differ materially in all these genera. The head is small 

 and subtruncated, mouth small, with the lower jaw the shortest, and overlapped 

 by the upper, a feature also noticed in Hyborhynchus. The isthmus of a moder- 

 ate size ; the eye well developed. The insertion of the ventrals takes places 

 posterior to the anterior margin of the dorsal. The latter is higher than long. 



