84 LIST OF FISH. 



VI. Another family has the tail of Trygon, but wants the sting 

 on the tail. 



1. Anacanthus, Ehrenb. — Tail without any fin. 



2. Urogymnus, Mull. & Henle. — Tail with a low fin on the upper 

 side, not reaching to the tip. 



VII. The Myliobatis, Cttv., form a family with large teeth, ar- 

 ranged as in a pavement or like mosaic-work ; the pectoral-fins are 

 separated from the head ; the tail has a fin in its root, and a spine 

 behind the fin. 



1. Myliobatis. — The teeth large in the middle, and small on the 

 sides of the jaw ; the nasal-valve has a smooth edge ; the fins of the 

 head united. 



2. JEtobatis, Mull. & Henle. — The fins of the head united by the 

 lower-jaw project far beyond the upper one ; only one row of teeth 

 in each jaw ; the nasal-valve deeply cut. 



3. Rhinoptera, Kiihl. — The fin on the head with a central ex- 

 cision ; teeth hexagonal : plates large in the middle of the jaws, di- 

 minishing in size as they reach the sides. 



VIII. The Cephalopter.e contain two genera: — 



1. Cephaloptera, Dura. — Mouth on the under side of the body ; 

 teeth small and pointed, or like tubercles in both jaws. 



2. Ceratoptera, Mull. >k Henle. — The mouth on the top of the 

 head ; the teeth, which are distinct only in the lower-jaw, are little 

 scales or leaves. 



M. Charles Buonaparte (Selachorum Tabula Analytica, 1838, 4to) 

 proposed to divide the family Raidae into the following tribes and 

 genera : — 



I. Raidae veri. — Body ending abruptly in a slender tail. 



1. Cephalopterini. — Head truncate, two-horned; tpeth minute, 

 placed in series ; pectoral-fins very broad ; tail very slender, long, 

 spine-bearing. — Cephalopterina. 



1. Ceraloptera. — Mouth superior ; teeth small, scale-like. 



2. Cephaloptera. — Mouth inferior ; teeth small, acute, or tuber- 

 culate in both jaws. 



2. Myliobatini. — Head ovate, produced: teeth large, flattened, tes- 

 sellated ; pectoral-fins very broad; tail very slender, spine-bearing. 

 — Myliobatina. 



