482 TRYQONIDiE. 



22. Trygon hystrix. 



Trygon hystrix, MiiU. 8^- Hcnle, p. 167; UOrUgny, Voy. Am. M6r. 



Poiss. pi. 15 ; ScJiomhurgk, Fish. Brit. Guiana, ii. p. 180, pi. 20 : 



Dumeril, Elasmobr. p. 608. 

 garapa, Schomhurgk, I. c. p. 182, pi. 21 ; Miill. ^- Trosch. in 



Sckoinb. Heis. iii. p. 642. 



Tail with a distinct cutaneous fold above and below, longer than 

 the disk. Disk ovate, entirely rounded in front. Upper surface 

 entirely covered with very small asperities, not densely placed, and 

 each with a stellate base. Only the margins of the disk are naked. 

 A row of thonis along the back of the tail to the spine ; old indivi- 

 duals with additional thorns on the sides of the tail. Four (two) 

 appendages at the bottom of the mouth behind the teeth. Brown 

 with round whitish spots, or reticulated with black. 



Guianas and Brazil. 

 rt. Fine specimen. Surinam. Purchased of Hr. Kappler. — Tlie 

 tail is perfect, and terminates in a slender, finless point, as in 

 other Trygons. 

 b. Young male. Santarem (E. Amazons). From Mr. Bate's Col- 

 lection.- — Entirely naked. 



23. Trygon orbicularis. 



Aiereha, Marcyr. p. 175 (cop. bv Jonston. De Pise. tab. 38. fig. 6, and 



Willuffhbt/, p. 68, tab. C 1. fig. 2). 

 Raja orbicularis, Bl. Schn. p. 361. 

 Trygon aiereba, Miill. §■ Henle, pp. 160, 196. 

 Pai-ati'ygon aiereba, Dmneril, Elasmobr. p. 594 (cop. M. Sf- H.). 



Tail with a very low cutaneous fold above, but not below, scarcely 

 longer than the disk. Disk ovate, without projecting snout. Eyes 

 extremely small ; spiracle with a very conspicuous projection behind. 

 Upper parts with small as^ierities, without larger tubercles. Colora- 

 tion uniform, (M. 4" H.) 



Brazil. 



/3. Hypolophus. The upper dental lamina is angularly bent, receiving 

 ivithin its concavity the lower lamina, which is somewhat pointed. 



24. Trygon sephen. 



Eaja sephen, Forsk. Descr. An. p. 17 ; Gm. L. i. p. 1508 ; LacSp. i. 



p. 123 ; Bl. Schn. p. 364. 

 Russell, Fish. Corom. i. p. 2, pi. 3. 

 Trygon sephen, Cuv. Eegne An. ; Eiipp. Atl. Fisch. p. 52, and N. W. 



Fisch. p. 69. 

 Raja sancur. Ham. Buch. p. 2; Blyth, Journ. As. Sac. Bcng. 1860, p. 37. 

 Trygon forskalii, Eii^ip. Atl. Fisch. p. 53, taf. 13. fig. 2. 

 Hypolophus sephen, Miill. ^- Henle, p. 170; Bleek. Verh. Bat. Gmi. 



xxiv. Plaq. p. 77 ; Cunt. Mai. Fi.sh. p. 429 ; Dumeril, Elasmobr. 



p. 616 ; bay, Fish. Malab. p. 279. 



Tail with a broad cutaneous fold below, but without one above, 

 about thrice as lone,- as the disk. Disk rhombic, with obtuse angles. 



