No. VI.] 



NOTICES OF THE FISHES. 



725 



Perca Fluviatilis, var. ? L. 



Occow, Cree Indians. Horn-fish, Piccarel, or Dore, of the Traders. 



(Jen. Perca, Lin. Sub-genus Perca, Cuv. Rig. Ann. ii. p. 293. ! 



Perca volgensis ? L. Gmel. or P. aspera? Pall. Itin. i. p. 461. 



The perch of Hudson's Bay differs in so many respects from the European one, that 

 it has been thought proper to give the following description of it. In its fins it bears 

 a stronger resemblance to the Perca Volgensis described by Pallas, although La 

 Cepede has referred the latter to the Lucio-Perca, which belongs to another of 

 Cuvier's sub-genera. 



Shape that of the common river perch. 



Colour. — The back and sides have a greenish colour, alternating in small spots 

 with king's yellow. The belly is white. The first dorsal fin is beautifully streaked 

 and clouded with different shades of yellowish-brown, and there is a dark patch of 

 venous blood-red on its posterior part. The second dorsal, pectoral, and caudal fins 

 are coloured and spotted like the back. The lower lobe of the caudal is tipped with 

 white. The ventral and anal fins are white, clouded with king's yellow. The latter 

 has, moreover, a slight tinge of red. The upper part of the head is coloured like the 

 back. On the cheeks there are some light shades of cherry-red, mixed with yellow. 

 The irides have a purple colour, intermixed with spots of pearl white. 



The scales are of a medium size, and rough from minute teeth on their exterior 

 edges. 



Head. — The lateral outline of the head, when the mouth is shut, is that of a cone, 

 whose summit, formed of the extremities of the upper and lower jaws, is rather obtuse. 

 The pre-operculum, of a thin crescentic shape, is entirely unconnected with the oper- 

 culum. Its posterior edge is free, and armed with small irregular tooth-like processes. 

 The inter-operculum is unarmed. The operculum and sub-operculum have conjointly 

 the form of a triangle, of which an entire side and the apex, which is lengthened out 

 by a membranous flap, are constituted by the sub-operculum. This latter bone is un- 

 armed, but the operculum has three or four small spines, which scarcely project 

 through the skin in the recent fish. The nape of the neck is armed on each side by 

 a rough bony plate, whose posterior edge projects a little. The cheek is large, fleshy, 

 and posterior to the orbit. There are several plates of scales on the anterior parts 

 of the cheek, the opercula, and occiput. The os frontis has numerous sulcse, which 

 appear through the thin skin that covers it. 



The eyes are large and prominent. 



The orifice of the mouth is large. The jaws are of equal length, but the upper 

 one is more obtuse, and receives into a depression, the more pointed extremity of the 

 lower one. The inside of the mouth is of a bluish-white colour, and in some places 

 a layer of nacre shines through the lining membrane. 



