32 SORTATION. 



By the two pectoral filaments, the ridged body, and the bifid 

 snout, we identify the armed gurnard (Peristethus), and by the two 

 stiff barbules under the chin, and the two dorsals wide apart, we 

 recognise the red mullet (Mullus). With one barbule we have four 

 genera (i), Phycis, distinguished by the ventral being replaced by 

 the bifid filament, from which the fish is known as the forkbeard ; 

 (2), Molva, the ling or " long-fish," in which the teeth are large in 

 the lower jaw, and the first dorsal is short ; (3), Lota, the burbot, in 

 which the first dorsal is also short, but there are no large teeth in 

 the lower jaw ; and (4), Raniccps, the lesser forkbeard, in which the 

 first dorsal consists of only three rays. 



In our next category we have those without barbules. Of these, 

 five genera are distinguishable off-hand by having finlets. In 

 Scomber and Auxis the dorsals are wide apart ; in Pdamys, Thynnus, 

 and Orcynus they are close together. The finlets fill the gap 

 between the tail and the second dorsal, and that between the tail 

 and the anal ; in the common mackerel (Scox.uer vernalis), they are 

 readily seen. There are three mackerels the ordinary species, 

 which has a banded back and a spotless abdomen ; the speckled 

 mackerel (S. punctatus), which has a thinly-streaked or speckled 

 back and a spotless abdomen ; and the Spanish mackerel (S. colias), 

 which has a banded back and a spotted abdomen. Auxis differs 

 from Scomber in having a distinct keel on the tail instead of two 

 slight ridges ; it is repre- /*X. 

 sented only by A . rochei, the \ >v 

 plain bonito. The three ) 

 genera in which the dorsals 

 are close together have 

 keel 3d tails. Pelamys (the 

 belted bonito) is recognis- 

 able by its long first dorsal, 

 which has more than twenty 

 rays ; the others have 

 shorter dorsals, one, Thyn- 

 nus (the bonito), having 

 seven finlets, the other, 

 Orcynus, having eight or F j g ^ I5 ._THORACic VENTRALS 



nine. To this last belong 



the tunnies, of which there are two on the British list the short- 

 finned tunny, O. thynnus, in which the pectorals do not reach the 

 finlets, and the long-finned tunny, O. germo, in which they do. 



This finlet group may as well be set forth in a table like 

 the rest 



Dorsals wide apart 



Tail with 2 slight ridges Scomber. 

 Tail distinctly keeled Auxis. 



Dorsals close together ; tail keeled 



First dorsal with over 20 rays Pelamys. 

 First dorsal with under 20 rays 

 Finlets 7 Thynnus. 

 Finlets 8 or 9 Orcynus. 



