380 



SYNOPSIS OF THE CYPRINIDiE OF PENNSYLVANIA. 



Mouth (typically) very small inferior, without barbels; pharyngeal teeth always hooked, and furnished with 



masticatory surface, latter sometimes on two teeth only, 0.4 — 4.0, 1.4—4.0, or 1.4 — 4.1, 2.4 — 4.1, and 2.4 4.2. 



Scales largo or moderate, a large surface exposed ; anal fin short. Length of alimentary canal a little less than 

 length of head and body. 



As deviating from the ordinary form, H. hsematurus has the mouth terminal, and H. hcterodon the mandible 

 longer, and mouth slightly oblique backwards ; it is indeed questionable on this account whether the latter be- 

 longs to the genus. The dentition, so far as known, is as follows : Teeth 4 — 4, II. hsematurus, stramineus, 

 dorsalis, rogius, procno, voluccllus; sometimes with one inner on one side, hcterodon; 1.4 — 4.0 storerianus; 

 2.4 — 4.1 hudsonius, 2.4 — 4.2 II. chalybacus, plumbeolus; of the above the masticatory surface is most exten- 

 sive, and the hook shortest in H. hasmaturus and II. tuditanus, which thus approximate Flybognathus. In the 

 species of that group the head is more massive; in the procne type the head is narrower, and the body more 

 compressed, while in sects. A, B, and C in part, the orbit is longitudinally oval. 



The genus, indeed, bears much resemblance to Hybognathus, and several of its species 

 have been described under the latter head by Girard and myself. Most of them arc of 

 small size, and all of weak organization. They are ornamented rather with lustre, than 

 hue, for I am not acquainted Avith any which display the bright colors of the Clinostomi 

 and Argyrei. They occur throughout those regions of the United States east of the 

 Eocky Mountains which have been as yet examined. 



The natatory bladder occupies the whole length of the abdominal cavity in the species 

 examined. Food, insects and crustaceans. 



Allied to this genus by the structure of its dorsal fin, alimentary canal, and teeth, is 

 Cochlognathus, Baird and Girard. It differs in the peculiar character pointed out by 

 Girard, the entire cutting edges of the jaws. The appearance of the known species is 

 much that of Hyborbynchus. 



I. Head 5.5 to 6 times in length (including caudal fin). 



Pectoral fins not reaching ventrals. 



A. Teeth +4 — 4+ ; mouth small inferior; lateral line complete; a broad lateral silver band. 

 Scales 6 — 38 — 3-4; teeth 2.4 — 4.1; eye three times in head; head five and two-thirds in total; muzzle 

 descending in profile, sometimes very obtusoly. A. 8 : squamosal region prominent. htjdsonius. 



Teeth 1.4 — 4.1; head one-sixth the length; eye one-fifth head; A. 9. 



STORERIANUS. 



II. Head 4.5 to 5 times in total length. 



B. Teeth 4 — 4 ; mouth inferior or horizontal, small ; lateral line complete. 

 a. Pectoral fins not reaching ventrals. 



Scales 7 — 43-4 — -4, not dark edged, 27 in front of dorsal, which is markedly nearer caudal than end of muz- 

 zle; muzzle very obtuse, mouth very small inferior; sides silvery, often with a dark band; no dorsal band, a dark 



