BATOIDEI. 153 



with skinny valvular coverings ; pectoral fins large, laterally expanded,, 

 but not attached to head ; dorsal fins spineless, in caudal region, no anal ; 

 males with claspers ; temperate and tropical seas ; intermediate between 

 the sharks and rays. Rhina Klein (Squatina Dum.), angel-fish, monk- 

 fish, viviparous, to 8 ft. 



Fam. 11. Pristiophoridae probably here. Shark saw-fish. Rostral 

 cartilage produced into long flat lamina, armed along each edge with teeth ; 

 Pristiophoms M. and H., Japan, Australia. 



Sub-order 3. RAJI (BATOIDEI). 



Gill openings ventral, five in number : spiracle always present, 

 without anal fin ; dorsal fins, if present, on the tail ; vertebrae 

 tectospondylous. Skates and Rays. 



The body is much flattened dorso-ventrally and the pectoral 

 fins are enormously expanded in an antero-posterior direction. 

 The five branchial apertures are entirely on the ventral surface 

 of the body. The spiracles are dorsally placed behind the eyes ; 

 they are wide and can sometimes be closed by a valve. It i& 

 probable that they are used for the intake of th3 respiratory 

 water when the fish is lying on the ground. The caudal region 

 is usually slender, and in some forms very much so. There is no 

 anal fin, and the dorsal fins when present are placed on the tail. 



The Pristidae and Rhinobatidae, which have a well-developed 

 caudal region and are intermediate in the form of their body 

 between the sharks and rays, are powerful swimmers, but most 

 of the Raji lead a more sedentary life on the bottom, rarely 

 coming to the surface. They feed chiefly on Mollusca and 

 Crustacea. A few deep-water forms are known, but they are 

 rarely taken below 100 fathoms. Most are shore-forms. 

 The Myliobatidae, which include the largest forms in the sub- 

 order, are however met with in the open sea. Some species 

 are confined to fresh water. They are for the most part 

 oviparous. The flesh of many of the species is eaten. Some 

 of the living families have existed since the Jurassic. 



Fam. 1. Pristidae. Saw-fishes. Snout much produced (rostral 

 process of cranium) with lateral saw-like teeth ; body somewhat shark- 

 like, the disc-like body gradually passing into the tail, which is com- 

 paratively thick, with two dorsal fins and a caudal fin, without serrated 

 caudal spine. Pristis Latham, tropical and sub-tropical, attain a con- 

 siderable size, with a saw 6 ft. long and 1 ft. broad at base. 



Fam. 2. Rhinobatidae. Tail long and strong with two dorsal fins, 

 a caudal and a longitudinal fold on each side, without serrated caudal 

 spine ; rayed portion of pectoral fins not continued to snout ; no electric 



