CHAPTER I: SHARKS. 



Characters of Selachians. General features of the Sharks. 

 Comb-toothed or Cow Sharks. Six-gilled Shark or Griset. 

 Seven-gilled Shark or Perlon. Sand Sharks and Elfin Sharks. 

 Sand Sharks or Slender-toothed Sharks. Elfin or Goblin 

 Shark. Mackerel Sharks. Porbeagles and Mako Sharks. 

 Great White Shark or Man-eater. Basking Shark. Thresher 

 or Fox Shark. 



We have already seen that the Sharks, together with their 

 relatives the Rays and the small and little-known fishes called 

 Chimaeras, constitute a distinct class, Selachii, and may be 

 collectively described as Selachians, a name derived from the 

 Greek word meaning a shark. The other two classes covered 

 by the popular term " fishes " are the Marsipobranchii 

 (Lampreys and Hag-fishes) and the Pisces (Bony Fishes). The 

 Marsipobranchii will not concern us here, as the members of 

 this group are all of small or moderate size, but we may briefly 

 indicate the principal differences between a Selachian and a 

 Bony Fish — between, say, a Shark and a Tarpon. 



The skeleton of a Shark is entirely cartilaginous or gristly, 

 and, although it is sometimes strengthened by the addition 

 of limy matter, there are never any true bones. The slits in 

 the walls of the gullet in the Shark open directly to the exterior 

 by a coi responding series of external gill-openings, 5 to 7 in 



