RAIA. 



317 



Rostrum soft flexible 



pectorals narrowly separated behind a short rostral process 



Psammobatis (page 370) 

 Rostral cartilage absent 



pectorals notched at the side, close together in snout 



Malacorhina (page 372) 



Raia. 



Rata (part) Linne, 1735, Syst. nat.; Ahtedi, 1738, Ichthyologia, Syn. p. 99, Gen. p. 70; Linne, 1758, 

 Syst., 1, p. 231. 



Disk subquadrangular to subcircular. Snout more or less produced and 

 pointed, with a stout prolongation from the skull as a rostral cartilage. Pec- 

 toral fins widely separated at the snout, not reaching its end. Eyes prominent, 

 with a fimbriate velum above the pupil. Nostrals with two valves, anterior 

 broad reaching the mouth, posterior folded in a tube; a nasoral groove. Mouth 

 transverse nearly straight. Teeth small, tessellate, varying from flat to sharp 

 and pointed. Spiracles close to the eye. Gill-openings small. Caudal mem- 

 branous. Ventrals notched. Tail with a fold along each side. Fossil in the 

 Eocene and later. 



The variation during the life of the individual in length of snout, length of 

 tail, width of disk, dentition, squamation, and coloration, not to mention the 

 variations in the sexes and among the individuals of a species, are so great that 

 it is thought better to group the Raiae according to localities, than to place 

 dependence on a synopsis of species the characters for which are drawn from 

 partial descriptions of single specimens widely diverse in degrees of maturity. 



European species ... 



Eastern North American species 



Western North American species 



Species from Japan to China and India 



South American species 



Species from South Africa to New Zealand 



page 318 

 page 335 

 page 343 

 page 349 

 page 356 

 page 363 



