30 THK FRESH-WATER FISHKs nK Kl'Koi'E. 



is still highly esteemed by the modern Greeks as a substitute for caviare. 

 Ancient and modern writers agree that the fish is in excellent condition when 

 it has been fattened for a month or six weeks in fresh water. They do not 

 breed in fresh water, but at the spawning 1 time retire to the salt marshes, 

 and commonly run up streams all round the Mediterranean. It is a foul- 

 feeding- fish, and was especially famous when caught in the Tiber, between 

 the bridges where the great drain emptied itself. And although the taste for 

 fishes so fed is past, they have not ceased to frequent the feeding-ground ; and 

 Dr. Badham narrates how he had often stopped to watch the net used in 

 this fishery perpetually revolving with the current, while some pallid water- 

 man has stood up feebly in the tethered old boat, wan as the Stygian ferry- 

 man, with ague in his veins and no quinine in his pocket, eyeing the 

 meshes, and putting forth a spectral arm to secure the small Bass or other 

 prey, and then letting down the net again into the floating feculence of the 

 river. 



Yarrell mentions that it had been successfully retained in Mr. Arnold's 

 fresh-water lake in Guernsey, and Steindachner mentions it as characteristic 

 of the embouchures of the rivers in the west of the Spanish peninsula. Its 

 ordinary length is from twelve to eighteen inches, though Couch measured 

 one that was thirty-one inches long. The weight is rarely in proportion to 

 the length, and does not commonly exceed twenty pounds in large fishes. 

 Its colour is grey on the back, becoming silvery at the sides, and as bright as 

 new silver beneath. There is a dark spot on the upper half of the operculum. 

 The young have small dark spots on the body. The fins are grey, with a 

 yellowish tinge in the pectoral and ventral fins. 



GENUS : Percarina (NORDMANN). 



This genus is essentially a Perch, in which all the fins are strongly de- 

 veloped except the first dorsal, and in which the palatine bone carries no teeth. 

 The form of the fish is compressed and elongated, resembling Acerina. The 

 mucus-cavities in the bones of the skull are greatly developed. The first 

 dorsal contains ten spines, and is united to the second dorsal by a narrow 

 membrane. The operculum has one spine ; the pre-operculum is denticulated. 

 The scales are small. The genus is known only from the south of Russia and 

 the adjacent borders of Austria. 



