99 



Centkarchus maculosus, Ayres. 



This species is very common in our markets, where it is sold 

 under the name of Perch, as are also several of the viviparous 

 fishes. It is brought from the waters of the Sacramento and 

 San Joaquin, and is one of our most esteemed fishes. The spe- 

 cimen from which my description is taken is of about the average 

 size ; it is eight and three quarters inches in length. 



Form oval, compressed ; greatest height two inches and nine 

 tenths, just behind the pectorals. Back arched ; forehead slightly 

 concave ; length of the head equal to the height of the body. 



Scales large and firm, covering all parts except the fins, the 

 top of the head, the throat, and the space anterior to the eyes. 



The posterior angle of the operculum is rounded and furrowed, 

 presenting the appearance somewhat of a large scale ; the edges 

 of the preoperculum, interoperculum, suboperculum, scapular 

 bone, and anterior suborbital are also finely denticulated. 



Lateral line nearly concurrent with the back ; number of scales 

 in its course about forty-two. 



Teeth fine, even, and crowded in the lower jaw, on the inter- 

 maxillaries, the vomer, palatine bones, and pharyngeals. 



The dorsal fin arises a very little posterior to the opercular 

 angle. The spinous portion is two inches and one fourth in 

 length, arched, highest at about the eighth ray, (three fourths of 

 an inch,) the first rays very short ; the last spinous ray seems to 

 constitute rather a part of the succeeding soft portion of the fin, 

 and is higher than the rays preceding it. The soft part of the 

 dorsal is rounded, one inch and one eighth in both length and 

 height. 



The anal is coterminal with the dorsal. The spinous portion 

 is eight tenths of an inch in length, the spines increasing in 

 length to the last, which is nine tenths of an inch high. The soft 

 part of the fin is an inch in length, the height being a little 

 greater. The spines of both anal and dorsal are stout and 

 strong, those of the anal especially. 



Pectorals rounded, an inch and a half in height. 



Ventrals fan-shaped, an inch and one tenth in height. 



Caudal slightly concave, an inch and three tenths high. 



