614 ORDER CHONDROPTERYGII. 



Their head is enveloped, as in the ordinary rays, by the 

 pectorals, which form a disk in general very obtuse. 



Some have the tail slender, and scarcely provided 

 with a fold in the shape of a fin ; and in the number 

 there are some with smooth backs. Such is 



R. pastinaca, L. Bl. 82. (the sting-ray.) With round 

 and smooth disk ; it is found in our seas, where its 

 spine or prickle is considered venomous, because 

 its dentations render the wounds which it inflicts 

 dangerous , . 



There are some also with the back more or less 

 spiny 2 . 



Others have the back tuberculous 3 . 



Others have the tail furnished underneath with a 

 broad membrane, and in this number is the species 

 with the back furnished with osseous and crowded 

 tubercles, R. Sephen, Forsk 4 . 



There is even one whose rounded body is altoge- 

 ther bristled with small prickles, and whose tail has 

 tubercles like those of the back in R. clavata, (R. 

 Gesneri, Cuv 5 .) 



But several have also the back smooth 6 . 



1 Add Tenkee Shindraki, Russ. i. 5. 



2 The Raie tuberculee, Lac. I. iv. I. The engraver has forgot- 

 ten the spine of the tail. Raia Sabina, Lesueur, Ac. Sc. Nat. Phil. 



3 Isakurrah Tenkee, Russ. i. 4. 



4 Add Wolga Tenkee, Russ. i. 3. 



5 There was only the figure of its tail, Gesner, 77. 



15 R. lymna, Forsk. p. 17. It is at least a species extremely 

 approximating to it which is represented, but without a spine, under 

 the name of Torpille, Lacep. I. vi. 1. and perhaps it is also the P. 



13 



