60 PERCTDiE. 



c. Adult : female skeleton. Ohio. From Mr. Frank's Collection as 



Perca americana. 



d. Adult: stiificd. Canada. 



e. Adult. N. America. From Mr. Warwick's Collection. 



f. g. Adult. N. America. From Mr. Wai-wick's CoEection. 



7;. Adult: stiiftcd. N.America. Presented by Edw. Doubleday, Esq. 

 y, /.-. Adidt : skins. Montezuma, U.S. From Dr. PameU's Collection. 

 J. Intestines of specimen c. 



SJceleton. — The stnicture of the single bones of the skull is exactly 

 the same as in the Common Perch ; the slight differences are the 

 following : the radiating streaks on the upper surface of the head and 

 on the operculum, which are to be seen also in the Common Perch, are 

 here deeper and more developed; the spines of the operculum are 

 more acute, and there is beneath the longest a third, much smaller, 

 but very conspicuous ; there are eight spinous teeth along the lower 

 limb, directed forwards. Vert. 21/20. The first interhaemal is 

 attached to the twenty-second vertebra, as in the Common Perch ; 

 and from an examination of the skeletons, I am still more inclined 

 to consider both to be varieties of one and the same species. 



Var. Peeca acuta. 



Cuv. (^ Val. ii. p. 49. pi. 10; Richardson, Faun. Bor.-Amer., Fishes, 

 p. 4 ; Dekay, New York Fauna, Fishes, p. 6. pi. 68. f. 222. 



D. 13-14 1 ^. A.|. 



Total length equal to 3-| the height of the body. Inferior edge 

 of operculum with a few rather strong denticulations ; inferior edge 

 of praooperculum with numerous weak spinous teeth ; opcrculimi 

 striated ; transverse rows ? ; transverse line ?. No black spot on the 

 first dorsal fin. 



Lake Ontario. 



3. Perca gracilis. 



Cuv. i!f Val. p. 50; Richardson, Faun. Bor.-Amer., Fishes, p. 4. 

 D. 13U. A. I-. 



I 14 6 



Total length equal to five times the height of the body. Inferior 

 edge of opercidum entire ; edges of praeopercidum with numerous 

 nearly equal, very small spinous teeth; operculum striated; more than 

 70 transverse rows of scales ; transverse line ^. A small black 

 spot on the hinder part of the dorsal fin. 



Lake Skaneateles (system of Ontario) ; Canada. 



a. Adult: stuffed. Canada. 



This species is considered by Holbrook to be a variety of Perxa 

 Jkivesccns. 



