FIXED-GILLED CH0NDR0PTEBYGUNS. 251 



weigh upwards of two hundred pounds. It is spotted when 

 young, assuming a more uniform and a paler tint with age*. 



In some species of Rays, individuals have been observed with 

 a recurved membrane on the middle of the disk, resembling 

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

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



Trygon, Adans\. 



Is recognised by the tail armed with a spine notched on both sides, 

 and the small, slender, and crowded teeth arranged in quincunx order. 

 The head, like that of the common Ray, is enveloped by the pectorals, 

 which generally form a very obtuse disk. 



The tail of some is slender and barely furnished with a fold in the 

 form of a fin ; of this number some have a smooth back. Such is 



R. pastinaca, L. ; Bl., 82. (The Sting Ray). Disk, round and 

 smooth ; inhabits European seas, where its spine is considered 

 venomous, on account of the dangerous nature of the wounds 

 inflicted by its serrated edgesj. 



The back of others is more or less spinous §, or tuberculated ||. 



Some again have a wide membrane on the under surface of 

 the tail, and the species, R. Sephen., Forsk.^J, whose back, 

 crowded with osseous tubercles, furnishes us with shagreen, is 

 of this number. The rounded body of one of them is even co- 

 vered with small spines, and the tail with tubercles like those on 

 the R. clavata, — R. Ges?ieri**, Cuv. Several, however, have a 

 smooth backj-f. 



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

 from the mosa'ique, Id., lb., XVI, 2; — the R. chardon (R. fullonica, L.), Rondel., 

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

 ruduta, Laroche, An. Mus., 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 R. 

 rostellata, Risso, pi. 1, and 2, Leeviraia, Salv., 142, is also a closely allied species ; — 

 R. asterias, Rondel., 350, and Laroche, An. Mus. XIII, pi. xx, f. 1. ; R. miraletus, 

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



Observe that no reliance whatever is to be placed upon the synonymes given by 

 Artedi, Linnaeus, and Bloch, as they are in a state of complete confusion, a circum- 

 stance principally owing to the fact 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 

 exceedingly doubtful in its application. 



f Pastinaca Truyon, or Turtur, ancient names of these fishes. 



X Add Tenkbe Shindraki, Russ., I, 5. 



§ The Raie tubercuUe, Lacep., I, iv, 1, in which the engraver has omitted the 

 caudal spine ; — Raia Sabina, Lesueur, Ac. Nat. Sc. Phil. 



|| Isakurrah-Tenkee, Russ., I, 4. 



«H Add Wolga-TenMe, Russ., I, 3. 



** They only had the figure of the tail, Gesner, 77. 



•f-f- R. lymna, Forsk., p. 17- It is at least a very closely allied species which is 

 figured, but without a spine, under the name of torpille, Lacep., I, vi, 1, and perhaps 

 it is also the P. yrabatus, Geoff., Eg. Poiss., Bl., XXV, i, 1. N. B. The lymne, 

 Lacep., I, iv, 2 and 3. is merely a common Trygon ; — R. jama'icensis, Cuv., Sloane's 

 Jam., pi. 246, f. 1. 



