30 SORTATION. 



extend on to the fins ; another, Pammelas (the black-pilot or rudder- 

 fish), has six or seven spines representing the first dorsal, and the 

 anal fin has two spines. The last, Gasterosteus, comprises our 

 familiar friends the sticklebacks, in which the scales 

 along the sides are replaced by scutes. In the smooth- 

 tailed stickleback these plates extend only to the tip 

 of the pectorals; in the half-armed stickleback they 

 extend half-way to the base of the caudal; in the rough- 

 tailed stickleback the plates are keeled at the base of 

 Fig. 13. the caudal. The other sticklebacks the three-spined, 

 HINGED four-spined, nine-spined, and fifteen-spined are readily 

 TOOTH OF recognisable by the number of their spines. 

 ANGLER. ^he wa y j s now c } ear f or the long voyage home. 



Our representative fish is not one of this unimportant 

 seven, nor was it one of the foregoing seventeen, being, as we have 

 said, an ordinary fish of ordinary shape, with nothing out of the 

 way about it. 



It has not three dorsals, that is the distinctive feature of the 

 genus Gadus, including the cod-fish (G. morrhua), which, like the 

 whiting, the haddock, the whiting-pout, and the power, has the 

 upper jaw the longer, and, like all of them except the whiting 

 (G. merlangus), has a barbule. It can be distinguished from the 

 other three by having a white lateral line, the haddock (G. agkfinus) 

 having a black lateral line, the two that remain having a brown 

 lateral line, the whiting-pout (G. litscus) being coppery and broadly 

 banded, and the power (G. minutus) silvery and without bands. 

 Three species of Gadus have the lower jaw the longer ; one of them 

 (G. virens), the coal-fish, has a barbule, those without a barbule 

 being G. poutassou (Couch's whiting), on which the lateral line is 

 straight, and G. pollachius (the pollack), on which it is curved ; the 

 two fishes differing much in colour, the pollack being greenish and 

 grey, the other silver and yellow. 



Nor has it two dorsals. The fishes having two dorsals can be 

 sorted into those in which the second dorsal is adipose and small, 

 and those. in which it is noticeably developed. 



Seven genera form the first division. In one, Paralepis, a rarity 

 in British waters, the anal fin extends to the caudal ; in the others 

 it is not nearly so long. Of these, another rarity, Maurolicus, has 

 the anal of three different heights, the lowest portion being in the 

 middle and the highest near the ventrals. Two from seven leaves 

 us with five, and the five, as it happens, are the salmonoids, all of 

 whom have less than twenty rays in their anal fins. The ridged 

 body of the argentine (Argentina), almost quadrangular in section, 

 distinguishes it at a glance. The long, high dorsal of twenty rays 

 or more characterises the grayling (Thymallus) ; the short maxillary 

 marks off Coregonus, the hautin (C. oxyrhynchus) having a projecting 

 snout, the gwyniad (C. clupeoides) a truncated snout, the vendace 

 (C. vandesius) a long lower jaw, and the pollan (C. poUati) equal 

 jaws and no truncation of the muzzle. Of the two genera with a 

 long maxillary, the smelt (Osmerus) is recognised by its dorsal rays 

 numbering n, and Salmo by their ranging from 12 to 15. Of 

 Salmo there are some twenty species or varieties, and as their many 

 trifling differences cannot be dealt with briefly, we will hold the 



