CATALOGUE OF SHIELD RErTILES. 



65 



Gvmnopus, sp., Bum. ^ Bib. Erp. Gen. ii. 477 ; Cat. Meth, 



R. 23. 

 Potamochelvs, Fitz. Sijst. Repf. 30 (1843). 

 Pelodiscus, Fitz. Si/st. Rept. 30 (1843). 



I had divided the American from the Old World species, 

 believing they had only seven ribs, but on re-examination I 

 find they both have the same number of ribs. 



The species may l)e thus divided according to their osteo- 

 logical characters, but they can only be used with certainty 

 by those vpho have a series of specimens of different ages 

 of each species before them. 



* First vertebral bone broad, crescent-shaped, early deve- 



loped ; episternal bones rather far apart at the base. 



f Callosities 2 ; dorsal disfi with two pits in front, one on 

 each side of the first vertebra. 



1 . Trionyx Rafeht. 



ft Callosities 4 ; dorsal disk with two pits in front. 



2. T. Argus. 



ttt Callosities 4 ; dorsal disk without any pits in front. 



3. T. perocellatus. 4. T. Nilolicus. o. T. Gangeticus. 

 6. T. ferox. 7. T. muticus. 



** First vertebral bone oblong, not developed until late in 

 life ; episternal bones elongate, close together at their 

 base. Callosities 4. 



8. Tyrse Javanicus. 9. T. carinifenis. 10. T. frenatus. 



They may be divided according to the colouring of the 

 head and limbs, but these colours often disappear or become 

 indistinct in the adult animal. 



* Head and limbs with subeqiial white spots. 

 1. Trionyx Rafeht. 2. T. Niloticns. 



* * Head and limbs with small and some larger ivhite spots. 



3. T. Gangeticus. 4. T. carhiiferus. 



*** Head spotted with longitudinal narrow black lines ; 

 lips and chin sj)otted. 



ft. T. perocellatus. 6. T. ferox. 



**** Head with diverging black streaks on the crown. 

 1 . T. Javanicus. 8. T. frenatus. 



***** Head with black-edged streaks enclosing the eye. 



9. T. Argus. 10. T. ferox (T. spiuiferus). 



The young of T. Niloticus, T. Gangeticus, T. Javanicus, 

 T. frenatus and T. ferox have the spinose tubercles on the 

 back in numerous parallel lines ; T. perocellatus has them 

 in distant, rather irregular lines ; and Chiton Indica has 

 close, isolated, I'ounded tubercles, very much crowded 

 together on the nape ; the side and hinder part of the 

 disk smooth. 



* Asiatic. 



1. Trionyx Rafeht. The Rafeht. Tab. XXX. 



Dull green. Head white-dotted. Sternal callosities 2 ; 

 lateral transverse, rather dilated at the inner end ; anterior 

 sternal bones far apart ; anterior part of the disk with two 

 rounded cavities between the broad lunate first and the 

 second vertebral bones. 



Tvrse Rafeht, Gray, Cat. Tort. B.M. 49. 

 Testudo Rafeht, Oliv. T'oy. Vers. ii. 453. t. 41. 



Shaw, Misc. t. 907. 

 Testudo Euphraticus, Baud. Rept. ii. 305. 

 Trionyx Euphraticus, Geoff. Ann. Mus. xiv. 17. 



Gray, Syn. 48. 

 Gymnopus Euphraticus, Bum. ^- Bib. Erp. Gen. ii. 498 ; 

 Cat. Meth. R. 22. 



Martin, Proc. Zool. Soc. 1840, 56. 



Hab. Tigris and Euphrates. Mus. Zool. Soc. 



a. Adult (stuffed). Euphrates. Presented by Mr. Loftus, 



Euphrates Expedition, 1850. 



b. Adult (without sternum). Euphrates. From the 



Zoological Society. Presented by Capt. Chesney. 

 Tab. XXX. Described by Mr. Martin, Proc. Zool. Soc. 



Osteology : — 



Skull of "a." Euphrates. 



The skull is much shorter and broader than that of 

 T. Niloticus. 



2. Trionyx perocellatus. The Eyed Boulousse. 



Tab. XXXL 



Back of young with distinct irregular lines of tubercles, 

 with six obscure spots. Head and neck olive ; lip and chin 

 with small white spots, with narrow brown streaks from 

 the front of the eyes to the lip, and from the back of the 

 eyes across the temple ; anterior dorsal bone large, broad. 

 Sternal callosities 4 ; hinder oblong, trigonal, oblique, with 

 the rugosities in concentric oblong rings. 



Tyrse perocellata, Gray, Cat. Tort. B.M. 48. 

 Trionyx jierocellatus, Cantor, Ann. i^' Mag. Nat. Hist. 

 T. tuberculatus. Cantor, MSS. 



T. stellatus, var. Javanicus, Schlegel, Faun. Japon. t. 5. 

 f 6.', t. 7. f. 1, 2. 



Hab. China ; Chusan. 



