14 SELACIIII : SQUALL — IV. 



Subclass SELACHII. (The Selachlvns.) 



This proup, sufHiicntly defined above, inrliules two orders, the 

 Sliarks and the Hays, — niarini; (isht-s of large size, abundant in 

 most seas. ((Ir. atXitx^oi, sliark.) 



Orders of Selachii. 



a. fiill openings Inti-ral SyUAi.i, 4. 



an. Gill openings ventral K.vi.i-:, 5 



Order IV. SQUALL (The Sharks.) 



The tyj)ical sharks are elongate in form, (juite unlike the skates 

 in appearance. Intorniediate forms connect the two groups so 

 closelv that the position of the gill o[)enings is the only constant 

 character by which the two orders can be separated. (Lat., a 

 shark, from Gr. yiiXfdr, allied to yaXf^, a weasel.) 



Note. — The Sharks are mostly fishes of the high seas, and any of the 

 larger .Vtlantic species may stray to our coast-s. Besiiles those here described, 

 the fiillnwing liave heen at least onie taken within our limits: — 



F.chinorhinus fpinogut ((Jnieliii), Cape t'od; Centrnrt/llium fobricii (lic'in- 

 hardl), ofT (iliuicestcr; Ccnlfniiriimnug calrlepis (IJocage & Cajx-llo), (llou- 

 fester; J'seitilotrincis microi/on (Cnpello), I^mg Island; Apriimtxion inotion 

 (Miiller & Ilenle); Isoijomphodon limbatui (Miiller & Hcnie), Wood's Holl. 



Omitting c.xtralimital families, wo have the following analysis of 



Families of Squall. 



a. Pectoral fins moderate, without deep notch at base in front; gill openings 5 

 b. Anal tin wanting. 



c. Dorsal tins each with a stout spine Sqcai.id.k, 4. 



cc. |)iirsul tins without spine SoMNiosir>.R, &. 



bb. Anal tin present; both dorsals without spine, the first inserted before 

 the ventrals. 



d. Caudal tin not lunnte, the n|)per lobe very much longer than the lower, 



with a notch below, towards its tip; side of tail without keel. 

 e. Last gill o|M'ning above ba.se of perioral. 

 f. Tail modiralely developed, not half length of rest of body; cyce 

 with nii'litatini; membrane. 

 g. Head kidney-slia|M-<l or hammer-shaped, much wider than long. 



SniYitMP.K, 6. 



gg. Head normally formed Gai.koioii.mh.k, 7. 



J^. Tail very long, as long as rest of body; no nictitating mem- 

 brane Atvoriiu.s, & 



