GENUS RAJA. 43 



Body above convex, olivaceous- red, darker near the 

 extremity of the fins; beneath flat, white; broader a short 

 distance behind the eyes; limb entire; head sloping, length 

 from the base to the middle of the nose nearly equal to the 

 distance between the eyes; eyes brown, oblique, not promi- 

 nent, distance between them moderate; spiracles oblique, 

 near and behind the eyes; nostrils small, placed nearer the 

 angles of the mouth than the middle of the nose; tip of the 

 nose truncated, quadrangular, descending, and closing the 

 mouth; septa short, narrow; mouth small, upper jaw undu« 

 lated, lower one a little prominent in the middle; armed 

 with several ranges of teeth, teeth dilated, and rhomboidal at 

 base, terminated by an acute point, recurved inwards, and 

 with a longitudinal depression before; lateral teeth more 

 suddenly attenuated. Attached to the superior jaw, 

 within, is a large membrane, lasciniated and loose at 

 the margin, serving probably to close the mouth like a 

 valve in order to retain the water and propel it through 

 the branchia; five conic membranous appendages are at- 

 tached to the lower jaw within, and support the superior 

 membrane during its inflation; and a longitudinal, cari- 

 nated, loose skin separates the palate in two equal parts. 



Branchial apertures, placed obliquely behind the angles 

 of the mouth, on an obliquely curved line; unequal, the 

 posterior one much smaller, and perpendicularly behind 

 the angles of the mouth; ventral fins rounded, with a small 

 process near the tail. 



Tail a little longer than the body, thicker and sub- 

 compressed at the base, attenuated, and at the point acute, 

 spine placed nearer the base than the tip; fins thick, smooth, 

 without distinct rays, black, elevated in the middle, gra- 

 dually disappearing tow-ards the extremities, superior fin 



