376 PHILOSOPHY OF ZOOLOGY. 



joined directly to the cranium, or by the intervention of a 

 single bone or stalk, to which the os hyoides is also attached. 

 A. Pectoral fins free, not coalescing with the snout. 

 The branhcial openings are at the sides. 



(1.) Mouth terminal. Eyes with a dorsal aspect. 



5. SQUATINA. Body depressed. No anal fin. Temporal 

 orifices. S. vulgaris, or angel shark. 



(2.) Mouth under the snout. Eyes with a lateral aspect. 



a. Snout produced, and armed with lateral teeth. 



6. PRISTES. Sawfish. Teeth of the snout regular, and 

 imbedded in sockets. P. antiquorum, a species which the 

 late Dr WALKER in his MS. says, " is found sometimes 

 in Loch Long." 



b. Snout abbreviated and unarmed. 



This group comprehends the great family of SHARKS, 

 the external and internal characters of which have been 

 very imperfectly investigated. 



(A.) Furnished with temporal orifices. 



(I.) With an anal fin. 



a. With two dorsal fins. 



(AA.) Teeth conical or pointed. In the two first ge- 

 nera, the anterior dorsal fin is situated nearly above the 

 pectoral fins, while in the third genus, it is placed nearly 

 over the ventral fin. 



6. SQUALUS. Branchial opening embracing nearly the 

 circle of the neck. Teeth without notches. Tail forked. 

 S. maximus, or basking shark, and S. Lelanonms^ or Loch- 

 fine shark. 



7. GALEUS. Tope. Branchial opening short. Teeth 

 notched. Tail-fin irregular. G. vulgaris, the Squalus 

 Galeus of LIN. 



8. SEYLLIUM. Nostrils near the mouth, with a groove 

 to the lips. Teeth notched. S. catulus, and var. canicula. 



