328 PISCES. 



(6. SELACHE.) Teeth small, conical, not denticulated at the sides : 

 temporal orifices, and anal, both present : branchial openings all 

 before the pectorals ; large, nearly surrounding the neck. 



(7. SPINAX.) Snout depressed: teeth small, cutting, in several rows: 

 temporal orifices present : anal wanting : branchial openings all 

 before the pectorals : a sharp strong spine in front of each of the 

 dorsals. 



(8. SCYMNUS.) Teeth in two or more rows ; in the upper jaw lanceo- 

 late, with the cutting edges rough ; in the lower jaw pyramidal, 

 compressed, with the cutting edges crenated : temporal orifices 

 present : anal wanting : no spines before the dorsal fins. 



74. ZYG^ENA. Head flattened horizontally, truncated 

 in front, with the sides very much produced, appearing ham- 

 mer-shaped ; eyes placed at the extremities of the lateral 

 prolongations ; the nostrils at their anterior margin ; mouth 

 beneath : pectorals moderate : branchial openings at the 

 sides of the neck. 



75. SQUATINA Body broad, flattened horizontally : 



pectorals large, extending forwards, but separated from the 

 neck by a cleft, in which are the branchial openings : head 

 round ; mouth at the extremity of the snout ; eyes above : 

 temporal orifices present : no anal : both dorsals further 

 back than the ventrals. 



(6.) PRISTIS. Bo&y elongated, flattened anteriorly; with the 

 branchial openings placed beneath : snout prolonged into a depressed 

 sword-shaped beak, armed on each side with strong sharp spines re- 

 sembling teeth: mouth beneath: temporal orifices present : no anal fin. 



76. RAIA. Body very much flattened, resembling a 

 disk : pectorals extremely large, uniting with the snout, or 

 with each other, anteriorly ; extending backwards to near 

 the base of the ventrals : mouth, nostrils, and branchial 

 openings, beneath ; eyes, and temporal orifices, above : 

 dorsals almost always upon the tail. 



(1. TORPEDO.) Tail short, and moderately thick: the disk of the 

 body nearly circular ; the part between the pectorals and the 

 head and the branchiae furnished with an electrical apparatus : 

 teeth small and sharp. 



(2. RAIA.) Tail slender ; furnished above, towards its extremity, with 

 two small dorsals, and sometimes the vestige of a caudal : disk 

 rhomboidal : teeth slender, close-set, arranged in a quincuncial 

 order. 



