60 



HIGH SCHOOL ZOOLOGY. 



Salmons by their large scales and toothless jaws. Both Salmon 

 and White-fish have certain appendages of the intestines which 

 are not present either in the Siluroids or Cyprinoids ; these are 

 situated at the junction of the stomach and intestine and are 

 known as the pyloric cceca. They serve to increase the digest- 

 ing and absorhiug surface of the intestines. Tliey ai*e small 

 and few in number in certain smaller marline Salmonidfe such 

 as the Capelin {Mallotus villosus) (Fig. 26) and Smelts 

 (Osmerus mordax) (Fig. 27), which in spite of their size are of 

 some importance as food-fishes. All of the Salmonidse have 

 cycloid scales, a pseudobranch and an adipose fin. 



Fig. 26.— The Capelin. Mallotus villosus. ^ 

 (U. S. P. C.) 



Fig. 27.— The Eastern Smelt. Osmerus mordax. \. 

 (U. S. F. C.) 



12. Another important family is that of the Clupeidae or 

 Heri'ings which are nearly all marine fish with a much com- 

 pressed body, a sei-rated abdomen and no adipose fin. The 

 commonest species ai-e the herring, C. harengus L. and the Shad, 

 C. sapidissima ; the former spawn in the sea, the latter ascend 

 rivers to do so. One siiecies of Clupea the Alewife (C. vernalis) 



