GENERA AND SPECIES. 73 



Acerina. Plate i. PERCH) JE. 



3. vulgaris, RUFF. Dorsal continuous ; scales rough to the touch ; 



lateral line prominent. 



The Ruff occasionally sp.elt with a useless " e " is the same fish 

 as the Pope. It has the two dorsal fins of the Perch running into 

 each other and forming one, though each is well marked. The 

 dorsal thus consists of 14 spines and from n to 13 rays; the anal 

 consists of 2 spines and 5 or 6 rays, the caudal of 18 rays, the 

 pectorals have 13 or 14 rays, and the ventrals the usual single spine 

 and 5 rays. In the dorsal the third and fourth spines are the 

 longest, and all the spines project further above the membrane than 

 those of the Perch. The tip of the pectoral is just half-way between 

 the snout and the fork of the tail. Of the two anal spines the first 

 is the longer. In the very distinct lateral line there are 40 scales, 

 and in them the tubes are double. The body is flat and easily 

 curved, except between the snout and the dorsal, where it runs 

 almost straight, so that the eye which is brown with a blue pupil 

 appears to be almost at the top of the head. The mouth extends to 

 the front edge of the eye, the upper jaw being the longer. There 

 are no teeth, except in the jaws, where they are in rows. There are 

 6 or 7 spines on the gill-cover, and i spiny scale at the shoulder, and 

 another at the angle of the pectoral fin. In colour the Ruff is olive 

 brown or greyish, with cloudy spots, and is paler on the sides and 

 whitish below. The fins are spotted and the ventrals are frequently 

 of an orange tint. The Ruff is a bottom-feeding fresh-water fish, 

 living in shoals, generally in deepish water in cool shady places. It 

 feeds on the fry of other fish, on insects, and on worms, and is 

 usually 3 or 4 inches in length, though it may be 7 inches or more. 



Acipenser. Plate xxvii. ACIPENSERIDM 



320. sturio, STURGEON. Shields along the back, the sides, and the 

 abdomen ; 4 barbules in a row. 



The Sturgeon has the dorsal fin close to the tail ; in it there are 

 from 35 to 40 rays, the anal having from 23 to 25 rays, the caudal 

 100 to 125 rays; the pectorals have a spine and 28 to 38 rays, and 

 the ventrals have 23 or 24 rays. The pectorals are placed very low and 

 close to the gills, arid the anal is close to the tail, its base beginning 

 under where that of the dorsal ends. The ventrals are in the tail 

 end of the body, a little further in front of the dorsal than the dorsal 

 is of the anal. The characteristic bucklers, or plates, number from 

 ii to 13 along the back, 23 to 26 along the side, those along the 

 abdomen being less conspicuous and varying greatly in number. 

 The mouth extends to beneath the small eyes, the snout is protracted 

 and often half as long as the head. In colour the Sturgeon is olive, 

 greenish, or yellowish, as the case may be. It is a solitary fish that 

 appears in our rivers in spring, and takes to the sea in winter, and is, 

 as a rule, caught when 5 feet long, though it attains 9 feet, and has 

 been recorded as long as 12 feet. 



F 



