106 FISH GALLERY. 



(listributefl over nearly all the trop)ical and subtropical seas ; and 

 Chlamydoselache , from Japan, Madeira, and Finmark. 



The Scylliid(2, or Dog-fishes, are mostly of small size. The 

 teeth are small and generally arranged in several series; the fins 

 are not armed with spines, a nictitating membrane is absent, and 

 the spiracle is always distinct. Two species of Scyllium are found 

 on the British coast — the '' Larger ^^ and "Lesser Spotted Dog- 

 fish,^' S. caniculum and S. catulus. They are coast-fishes, living 

 on the bottom, and feeding on crustaceans, dead fishes, &c. 

 The Zebra- or Tiger-Shark, Stegustnma tigrinum, one of the 

 commonest and handsomest Sharks of the Indian Ocean, reaches 

 a size of 10 to 15 feet. Crossorhinns (Case 39), a genus of ground 

 Sharks from the Indo-Pacific Ocean ; they are sluggish and lie 

 concealed on the bottom watching for their prey. In accordance 

 with this habit their colour closely assimilates that of a rock or stone 

 covered with short vegetable and coralline growth, a resemblance 

 which is increased bv the frond-like tentacles on the side of the head. 

 [Case 40.] The Cestraciontid(B (Case 40) have, like the preceding, several 

 series of teeth simultaneously in function ; each of the dorsal fins 

 is armed with a spine. This family is one of particular interest, 

 because representatives of it occur in numerous modifications in 

 Primary and Secondary strata. Their dentition (of which pre- 

 parations are shown in Table-case C) is adapted for the prehension 

 as well as mastication of crustaceous and hard-shelled animals. A 

 few recent species are known, from various parts of the Pacific Ocean. 

 The Spinacid(S, or Spiny Dog-fisries (Cases 39, 40), so called on 

 account of the spine with which their dorsal fins are usually armed, 

 are a family containing numerous genera, the majority of the species 

 being of small size. Acanthins is the best known, the two species, 

 A. vulgaris and A. b lainvil Hi, occnr ring on the British coast. The 

 species of Cenfrophorus live at a considerable depth, perhaps at a 

 greater depth than any of the other known Sharks. The Portuguese 

 fishermen fish for them in 400 or 500 fathoms with a line of some 600 

 fathoms in length. The Greenland Shark [Lamargus borealis) is an 

 inhabitant of the Arctic regions, rarely straying to the latitudes of 

 Great Britain. It grows to a length of about 1 5 feet, and is extremely 

 voracious. The "Spinous Shark" [Echinorhinus spinosus) is a 

 ground Shark, probably living at some depth, and but accidentally 

 coming to the surface. More frequently met with in the Medi- 



