FISHES 



285 



of the larger sharks. The Common Tope (Galeus canis) is a 

 small shark with a very wide distribution, and is a well-known 

 British species. It may attain a length of 6 feet or more, and 

 in colour is dark grey above and white below. The body is 

 slender and the snout prolonged and pointed. A somewhat 



A. 



PECTORAL FIN 



Fig. 166. Sharks, reduced to various scales 



A, Spotted Dog-Fish (Scyllium canicula). B, Blue Shark (Carcharias glaucus). 

 c, Hammer-headed Shark (Zygcena malleus}. 



smaller form, common in British seas and widely distributed over 

 the world, is the Smooth Hound (Mustelus lcevis\ which can 

 easily be distinguished from the Tope by its blunter snout, and 

 the presence of whitish spots on the back. The most remarkable- 

 looking member of this family is undoubtedly the Hammer-headed 

 Shark (Zygcena malleus], in which, as the name indicates, the head 

 is broadened out like a T by the presence of projections upon 

 which the eyes are situated. It has occasionally been taken in 



