Rep'odactice Onjans of Sparus Cenirodouti(s. 



21 



The angle between the last raj^ of the dorsal and anal tins and 

 the edge of the body is usually filled with a membrane (^mb., Fig. 98). 

 This membrane varies in its size, and is more usually noticeable in 

 the larger fishes. In the small fishes it is very slight. 



The pectoral fin had 17 to 19 rays. The upper half of the fin is 

 composed of rays which have thin tips ; the lower half of the fin is 

 composed of swollen raj's, the tips of Avhich are usually siiigle and 

 slightly separated from one another. The last ray is sometimes thin, 

 and in one specimen it was branched. Most of the rays of the upper 

 half of the fin have two points. In one fish, of the 9 thin rays the 

 4th to 9th had split tips. 



The ventral fin consists of one spine-ra}^ and five soft rays. The 

 spine-ra}- is tightly bound to the first soft ray. A membrane fills the 

 angle between the last soft ra}' and the surface of the abdomen. 



The vertebrge numbered 30 and o 1 . Among the small fishes the 

 most frequent number of vertebrae was 30. In 15 fishes, measuring 

 from 38 to 50 cm. in length, the number was 31. 



The vertebra bearing the first htemal spine was in 9 fishes (19 to 

 21 cm. long) the 12th (total number, 30). while in the 15 larger fishes 

 it was the 13th. 



Difierences have been noted between large fishes. Some fishes are 

 not so deep nor so thick as others. Certain of these lighter fishes 

 which were landed in December and January probably came from 

 Icelandic waters. Six of them, measuring from 39 to 50 cm. in total 

 length were compared with a North Sea specimen (May) measuring 

 37 cm. in length. The Iceland fishes were of a bright red; 

 the dark bars were hardly to be detected at all. The North Sea 

 fish had a larger eye, broader dorsal and anal fins, with, in each 

 case, larger and stouter spines, a deeper and thicker body, than 

 the other group. The latter had a bigger tail fin, and the hind 

 margin of that fin was rather more deeply concave than in the 

 North Sea fish. These characters w^ere measured (in an.) on the 

 North Sea specimen and on an Iceland fish, and the results are shown 

 in the followins; tat)le : — 



The least spread of the tail was the breadth of the fin when it was 

 smoothed out, with each fin-ray close to its neighbour. The ventral 

 ramus of the tail was measured from the root of the tail, approximatel)^ 

 at the beginning of the outer rays. 



The North Sea specimen was compared with two other fishes 

 measuring 48 and 50 cm. in length respectively, which had been landed 

 fresh and ungutted at Aberdeen ; they, no doubt, came from the North 

 Sea. In the 48 cm. fish the dorsal fin \\as narrower and the spines 

 were not so stout as in the specimen 37 cm. long. The fish 

 50 cm. long had the fin as broad and the spines about as stout as 

 in the deep fish. 



