4S2 TRYGONIDJE. 



22. Trygon hystrix. 



Trj'gon hystrix, Midi. Sf Henle, p. 1G7 ; nOrhigny, Voy. Am. M6r. 



Poiss. pi. l-'j ; Schombiirf/k, Fish. Brit. Guiana, ii. p. 180, pi. 20 ; 



Dnntcril, Ela^tnohr. p. G08. 

 garap.a, Schomhuryk, I. c. p. 182, pi. 21 ; MiUl. 8f Trosch. in 



Schonih. lieis. iii. p. 042. 



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, a«.d 

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

 A row of thorns along the back of the tail to the spino ; 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.. 

 a. Fine specimen. Surinam. Purchased of Hr. Kappler.— The 

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

 other Trygons. 

 h. Young male. Santarem (R. Amazons). From Mr. Bate's Col- 

 lection. — Entirely naked. 



23. Trygon orbicularis. 



Aiereba, Marcgr. p. 175 (cop. by Jondon. De Pise. tab. 38. fig. 6, an(', 



WiUmjhhri, p. 68, tab. C 1. fig. 2). 

 Raja orbicularis, BI. Schn. p. 361. 

 Trygon aiereba, Midi, c^ Henlc, pp. 160, 19G. 

 Paratrygon aiereba, Dnmeril, Elasmohr. p. 594 (cop. M. Sf IL). 



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 asperities, without larger tubercles. Colora- 

 tion uniform. (31. 4" ff-) 



Brazil. 



/3. llypoloplius. T/ic upper dental lamina is a)tr/idarl>/ bent, receiviitcr 

 within its co)icavitif the loiver lamina, which is smneichat pointed. 



24. Trygon sephen. 



Raja sephen, Forsk. Descr. An. p. 17 ; Gm. L. i. p. 1508 ; Lacep. i. 



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

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

 Trygon sephen, Cuv. Regne An. ; Riipp. Afl. Fisch. p. 52, and N. IF. 



Fisch. p. 69. 

 Raja sancur. Ham. Buch. p. 2; Blyth,Journ. As. Sue. Beng. 1860, p. 37. 

 Trygon forskalii, Riqyp. Atl. Fisch. p. 53, taf. 13. fig. 2. 

 n^'polophus sephen, Miill. S,- Hcnle, p. 170; Bleek. Verh. Bat. Gen. 



xxiv. Rlaq. p. 77; Cant. Mai. Fish. p. 429; Dumcril, Elasmohr. 



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



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

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



