17. TRYGON. 473 



spine, serrated on each side. Body smooth or with tubercles. Pec- 

 torals united in front. Nasal valves coalescent into a quadrangular 

 flap. Teeth flattened. 



Seas of the temperate and tropical regions. 



The species may be arranged thus : — 



a. Trygon. Dental laminse transverse, not or but slightly undu- 

 lated. 



aa. Tail without any cutaneous fold (HinMntura), p. 473. 



bb. Tail ^vith an inferior or superior cutaneous fold {Tryguti), 

 p. 477. 

 ^. Hypolophm. The upper dental lamina is angularly bent, re- 

 ceiving within its concavity the lower lamina, which is some- 

 what pointed : p. 482. 



«. Trygon. Dental laminoi transverse, not or but slightly undulated. 

 aa. Tail without any cutaneous fold, 



1. Trygon uarnak. 



Raja uarnak, Forsk. Descr. Anim. p. 18. 



Trygon russelhi, Gray, Ind. Zool. c. fig. 



Pastinachus uarnak, Eiijip. iV. IF. Fisch. p. G9, pi. 19. figs. 2 a & 2 6. 



Trygon uai-nak, Mull. S,- Henle, p. 158; Cant. Mai. Fish. p. 423; 



Bleek. Verh. Bat. Gen. xxiv. Flag. p. 69 ; Blyth, Journ. As. Sac. 



Calc. 18G0, p. 44 ; Dumeril, Elasmobr. p. 58.5 ; Day, Fish. Malab. 



p. 277. 

 variegatus, M'Clell. Calc. Journ. Kat. Hist. 1841, 1. p. GO, pi. 2, 



fig. 2; Blyth, Journ. Asiat. Soc. Beng. 1860, p. 43; Dumeril, I.e. 



p. 43. 

 uarnacoides, Bleek. I. c. p. 72, or Nat. Tyds. Ned. Ind. iii. p. 738 ; 



Dumeril, I. c. p. 586. 



undulatus, Bleek. I. c. p. 70 ; Dum6ril, I. c. p. 586. 



pareh, Bleek. I. c. p. 71, or Nut. Tyds. Ned. Ind. v. p. 401 ; Du- 



meril, I. c. p. 590. 



pastinacoides, Bleek. I. c. p. 75. 



ellioti, Blyth J Journ. As. Soc. Beng. 1860, p. 41. 



Tail without cutaneous fold, exceedingly long and slender, about 

 thrice as long as the disk. The snout is rather pointed, forming a 

 distinct projection in the anterior profile, the margins meeting at an 

 angle which is fully or less than a right one. One or more large 

 tubercles in the middle of the back : young examples are smooth ; 

 but with progressing age the neighbourhood of the central tubercles 

 becomes covered with small tubercles, which gradually spread over 

 the entire dorsal surf ice of the head and trunk, and fiiuilly envelope 

 the tail also. There is, besides, much variation in the deveh>pment 

 of these small tubercles, according to the individuals. There are no 

 large tubercles in the median line of the tail. Disk about as broad 

 as long. Uniform brown, or with numerous dark-brown spots ; 

 tail of the young with alternate brown and ^^•hitish rings. 



Indian Ocean and archipelago. 



