Dr. Horsfield and Mr. Vigors on Gymnura Rajflesii. 247 



an interest, that we caused a plate of it to be engraved for the 

 Journal. Since we first examined this animal, we have been for- 

 tunate enough to discover, in the same collection, an adult speci- 

 men, that had been preserved in spirits. We are thus enabled to 

 give a perfect description of the species, and at the same time, 

 having all the materials complete before us, to characterize the 

 group to which it belongs, and which appears to us very distinct 

 from any hitherto described. 



Sir Stamford Rafiles referred the species to a Linnean genus, 

 proposing for it the specifick name of gymnura. Although how- 

 ever he did not nominally raise it to the importance of a genus, 

 he gave so clear and accurate a description of its generick cha- 

 racters, that we do not hesitate in attributing the first indication 

 of the group to him. We shall consequently adopt his specifick 

 name as generick, and give the characters as he himself described 

 them, entering only with more minuteness into the details. The 

 accompanying plate exhibits the younger specimen, which is in 

 much liner condition for representation than the adultj and equally 

 indicative of the species. In a future number of the Journal we 

 shall give the head and system of dentition of the adult, and hope 

 at the same time to be ab!o to add some details of its internal 

 economy. 



Genus. Gymnura, Raflles. 



Incisores supra 2, remoti, maximi, subcylindrici, aplce rotun- 

 dato ; infra 6, quatuor intermcdii approximati, breviusculi, pro- 

 clives, compressi, pagina anteriori convexa, interiori plana, seal- 

 pro rotundato, duo laterales abbreviati, acuti. Laniarii supra 

 utrinsecus 2, ab incisoribus remoti illisque breviores, conici, antici 

 niajores ; infra utrinsecus 1, maximus, cpnicus, subarcuatus intror- 

 sum spectans. Molares supra utrinsecus 8, a laniariis remoti, 

 tres antici unicuspides, primus elongatus sectorius, secundus et 

 tertius abbreviati, quartus cuspide conica elongate, ad basin 

 gradu postico et exteriori abbreviato, quintus cuspide exterior! 

 longissirai interiori abbreviatii. ; sextus et septimus maximi, multi- 

 cuspides, cuspidibus subabbreviatis rotundatis, octavus minor sub- 

 tritorius, cuspidibus obtusioribus ; infra 7, tres antici unicuspides, 



