OS NEW YORK STATE MUSEUM 



jaws without cartilaginous sheath; jnuciferous system moder- 

 aicly developed; opercular apparatus well developed, the sub- 

 opercle broad; isthmus moderate; pharyngeal bones remarkably 

 thin, laterally compressed, with a shallow furrow along the an- 

 terior margin on the inside, and another more central on the 

 outline of the enlarged surfaces; teeth very small, compressed, 

 nearly equally thin along the whole inner edge of the bone, form- 

 ing a fine, comblike crest of minute serratures, their cutting- 

 edge rising above the inner margin into a prominent point; gill 

 rakers slender and stiff above, becoming reduced downward; 

 scales large, about equal over the body; lateral line well de- 

 veloped, nearly straight; dorsal fin long, nearly median, some- 

 what in advance of ventrals, falcate, its anterior rays elevated, 

 often filamentous; caudal fin well forked, the lobes equal; anal 

 fin comparatively long and low, few-rayed; ventrals rather 

 short, usually with 10 rays; pectorals short, placed low; air 

 bladder with two chambers. Size medium or rather large. 

 (After Jordan and Evermann) 



55 Carpiodes thompsoni Agassiz 

 Lake Carp- Drum 



Catostomus cyprinus THOMPSON, Hist. Vermont, 133, 1842. 



Carpiodes tlioni'psoni AGASSIZ, Am. Jour. Sci. Arts, 191, 1855; COPE, Proc. 



Ac. Nat. Sci. Tbila. 285, 1864; JORDAN, Man. Vert. 297, 1876; JORDAN. 



Bull. 12, U. S. Nat. Mus. 198, 1878; JORDAN & GILBERT, Bull. 16, U. S. 



Nat. Mus. 119, 1883. 



Body short and stout, the back strongly arched, the greatest 

 depth two fifths of the length to base of caudal fin; head short, 

 about one fourth of length, the snout acutely pointed; lips thin, 

 white, meeting at a wide angie; tip of lower jaw much in ad- 

 vance of nostrils; maxillary reaching to below- front of orbit; 

 eye small, about one fifth length of head; dorsal about median, 

 its rays considerably produced, the longest two thirds as long 

 as base of fin; scales rather closely imbricated, 8-39 to 41-6. 

 D. 27; A. 7; V. 10. 



Abundant in the Great lakes region. Found in Lake Cham- 

 plajn. 



