CHONDROPTERYGII BRANCHIIS FIXIS. 293 



Europe which are not yet well determined. Their flesh though hard 



is eaten. 



R. clavata, L.; the male, BL, 84, under the name of rubies, 

 the female. (The Thornback.) Distinguished by its I'ough- 

 ness and the thick, oval, bony tubercles, each of which is fur- 

 nished with a recurved spine, that are irregularly scattered 

 over its two surfaces. Their number varies greatly. 



R» Tubus, L.j'Lacep., I, v (The Rough Ray), differs from 

 the clavata in the absence of the tubercles. The male of both 

 species, however, has hooked spines on the front and angle of 

 the wings, their posterior edge being similarly furnished in the 

 female. The appendages of the male are very long and com- 

 plex.(l) 



R. batiSf L.; R. oxyrhinchus major, Rondel., 348. (The 

 Skate.) Superior surface of the body rough, but spineless, with 

 a single row of spines on the tail. It is the largest of all the 

 species, and is sometimes found to weigh upwards of two 

 hundred pounds. It is spotted when young, assuming a more 

 uniform and a paler tint with age. (2) 



In some species of Raia individuals have been observed with 

 a recurved membrane on the middle of the disk, resembling a 

 fin. Such, in the R. aspera,h the Raie Cuvier, Lacep., I, vii, 1. 

 I have seen the same in a R. batis. The 



(1) N.B. The R. batis, Penn. Brit. Zool., No. 30, is nothing- more than this 

 rubus, Lacep. The rubus, Bl., 84, which is the B. clavata, Will., is, if not a 

 species, at least a variety remarkable for the tubercles that are scattered over 

 both surfaces. There is also a variety, R. oculata aspera, llondel. , 351, marked 

 with an ocellated spot on each wing'. 



(2) Add the R. undulata, Lacep., IV, xiv, 2, which differ but little, or not at 

 all, from the mosaique. Id., lb., XVI, 2;— the R. chardon {R. fullonica, L.),Rondel., 

 356, figured under the name o^ oxyrhinchus, Bl., 80, and Lacep., I, vi, 1; — the R. 

 rudula, Laroche, An. Mas., XIII, 321, is closely allied to it. — The R. lentillat {R. 

 oxyrhinchus). Rondel., 347, of which the Raie bordee, Lacep., V, xx, 2, or the jR. 

 rostellata, Risso, pi. 1 and 2, Laeviraia, Salv., 142, is also a closely allied spe- 

 cies; — R. asterias. Rondel., 350, and Laroche, An. Mas. XIII, pi. xx, f. 1; R. mi- 

 raktus, Rondel., 349; — R. aspera, Rond., 356. 



No rehance whatever is to be placed upon the synonymes given by Artedi, 

 Linnseus, and Bloch, as they are in a state of complete confusion, a circumstance 

 principally owing- to the fiict of their employing, as a chief character, the number 

 of rows of spines on the tail, which varies both with the age and sex, and cannot 

 serve to distinguish the species. That of sharp or blunt teeth is likewise not 

 sure. 



