52 IDENTIFICATION. 



fact of its having eight spines we know it can only be that known as 

 the nine-spined stickleback, which may have 8, 9, 10, or n spines. 



Yet another. How many dorsals are there ? Three. Three ? 

 It can only be Gadus ; but what species ? Refer to the ninth 

 chapter. Is the upper jaw longer than the lower ? No. Has it a 

 barbule ? No. We have reduced the possibles to two. Is the lateral 

 line curved. Yes, and it has a greenish back and golden and silvery 

 sides, and is altogether a good-looking member of the cod family. 

 It is a pollack. 



Here is another with three dorsals, which is copper-coloured and 

 broadly banded, and has blackish fins and a brown lateral line. Is 

 its upper jaw longer than the lower ? Yes ; and it has a barbule. It 

 is a whiting-pout. 



Let us have one with an adipose dorsal. Does the anal extend 

 to the caudal ? No, the anal does not reach the tail. Has the anal 

 more than twenty rays ? No. Is the body ridged ? No. How many 

 dorsal rays are there ? A fair number ; it is a long dorsal. Are 

 there more than eighteen ? Certainly. Then it is Thymallus, the 

 grayling. 



Next, we take one with two dorsals fully developed. Are there 

 any barbules ? No. Are there any finlets ? No. What is the 

 position of the ventrals ? Jugular. Wide apart ? No ; close 

 together. How many rays are there in the first dorsal ? Ten. 

 Then it is the hake (Merluccius), which, by the way, has hinged 

 teeth like the angler. 



Let us have a representative of the single dorsals. Has it any 

 ventrals ? Yes, and they are thoracic. What is the anal like ? Has 

 it a spine and fourteen rays ? No ; it has two spines. Two spines ? 

 How many rays ? Five. Enough ; it can only be the ruff (Acerina), 

 which its rough scales prove it to be. 



Here is another, with a single dorsal and abdominal ventrals. It 

 has no barbules. Its abdomen is not sharply compressed, but gently 

 rounded. Its dorsal is not pla-ced over the anal, but midway along 

 the back ; and the anal is rather long, and seems to have ten rays, 

 though, perhaps, there are eleven. The genus can only be Leuciscus. 

 But what is the species ? The lateral line is distinct all along 

 the body, and there are five rows of scales between it and the ven- 

 trals, which, with the silvery side and bluish back, show the fish to 

 be a dace (L. vulgaris). 



Finally, we will have another, and run it through the mill. Its 

 body is not horizontal ; its tail fin is rather large ; the tail is not 

 heterocercal ; the lobes of the tail are equal ; and the tail is in a 

 line with backbone. There is nothing eccentric about its shape ; 

 there is nothing to show that it ever had two dorsals ; it has one 

 dorsal, and the ventrals are neither jugular nor thoracic, but 

 abdominal. It has no barbules; the abdomen is not rounded at 

 either end, but compressed all along; and the upper jaw does not 

 project. The genus is Clupea, The dorsal is nearer to the head 

 than to the tail ; the ventrals are below the middle of the dorsal, 

 and have six rays and to end all this it can only be the pilchard, 

 which we might have recognised at sight by its large scales. 



