Hybrid between the Bream and the Radd. 163 



Depth of body 2£ to 2§ in the length, length of head 4£ to 4f . 

 Snout as long as or longer than the diameter of eye, which is 

 4^ to 5} in the length of head ; interorbital width 2% to 2\ 

 in the length of head. Mouth oblique ; jaws equal ante- 

 riorly or the lower the shorter; maxillary extending to below 

 the nostrils, or slightly beyond. Dorsal 11-13, with 8-10* 

 branched rays ; base above the interspace between pelvic and 

 anal fins ; free edge straight or concave ; longest ray nearly 

 as long as the head. Anal 18-21, with 15 to 18 * branched 

 rays; free edge emarginate. Pectorals as a rule not reaching 

 the pelvics, which do not usually extend to the vent. 

 Caudal forked, the lower lobe the longer. Lateral line 

 decurved, running at about i- the height of the body in the 

 middle of the length of the fish. 46 to 50 scales in the 

 lateral line, 9i to 10^ in a transverse series from origin of 

 dorsal fin to lateral line, 3^ to 5^ between lateral line and 

 base of pelvic fin. Sides more or less silvery ; back darker ; 

 fins dark greyish. 



Fourteen specimens in the British Museum measure from 

 230 to 340 mm. in total length (to the end of the middle 

 rays of the caudal fin). Nine of these have been sent from 

 Lough Erne during the last three years by Major Trevelyan ; 

 three from Colebrooke, Upper Lough Erne, were received 

 from Sir Victor Brooke in 1871 ; one from Thetford was 

 presented by Dr. Gunther in 1879 ; and one is a skin from 

 YarrelFs collection. 



According to Major Trevelyan, this hybrid is known to the 

 Lough Erne fishermen by the name of " white roach," in 

 contradistinction to the " red roach " or " rudd." The largest 

 specimen sent by him (330 mm.) weighed 2 pounds, but he 

 has good reason to believe that specimens of 2^ pounds 

 weight have been taken. 



The comparative abundance of these fishes in Lough Erne 

 is rather remarkable, and it would be of interest if anything 

 could be ascertained as to their breeding, whether they are 

 fertile together, &c. 



Those characters of the parent species and of the hybrid 

 which can be numerically expressed may be presented in 

 tabular form, thus : — 



* Of fourteen specimens, twelve have 9 branched rays in the dorsal 

 fin, one has 8, and one 10. Four have 18, seven 17, two 16, and one 15 

 branched rays in the anal fin. 



