HYODONTIDvE. — OVI. 277 



no barbels; no adipose fin; lateral line distinct; abdo- 

 men not serrated, compressed; moderate sized teeth on 

 jaws, vomer, sphenoid, hyoid, pterygoid and palatine 

 bones; tongue with large teeth; head short, deep; eye 

 very large; gill openings wide; one pyloric appendage; 

 air bladder simple. Three species, inhabiting our West- 

 ern Streams and the Great Lakes. 



/. HYODON, LeSueur. Moon Etes. 

 * Belly scarcely carinate ; dorsal rays 12. (Myodon.) 



1. H. tergisus, LeSueur. Mooir Eye. Silver Bass. 

 Toothed Hbeeing. Depth 3^ in length; head 4f; 

 snout rounded, shorter than the large eye, which is 3^ in 

 head; scales largest on the flanks; pale olivaceous above, 

 sides brilliantly silvery; D. 3, 13; A. 30; V. 7; lat. 1. 

 59; length 1 foot. Great Lakes and Mississippi Valley, 

 abundant; one of our most beautiful fresh water fishes; 

 variable ; it has been described under many names. 



2. H. selenops, Jordan & Bean. Southeen Moon 

 Eye. Body elongate, not greatly compressed; depth 4 

 in length; belly in front of ventrals transversely rounded 

 (very slightly carinated in S. tergisus); head 4^ in 

 length; eye very large, 2J in head; D. 3, 12; A. 27. 

 Cumberland River and South. 



** Belly strongly carinated both before and behind ventrals ; dorsal 

 fin, very small, of nine rays ; (Elattonistius, Gill & Jor.) 



3. H. chrysopsis, Rich. Golden Moon Eye. Body 

 deep, closely compressed; depth 3:J- in length; head 4rJ-; 

 eye moderate, 3-|- in head; pectorals much shorter than 

 in the other species, nearly as long as head, about reach- 

 ing ventrals; length of longest dorsal ray half greater 

 than base of fin (about equal to it in the other species) ; 

 D. 3, 9; A. 31; lat. 1. 58. Minnesota and northward. 



