4. IiniNEMTS. — 5. HYDRASPrs. 210 



Platemj's na^uta, Straiich, Chelon. Stud. pp. 47 & IGO (18G2). 



raniceps, Sf ranch, I. c. p. 47. 



Il>draspi3 uiaculata, Gray, Ann. ^- Mar/. N. II. (4) xi. p. 305 



Carapace much depressed, with at least a trace of a vert(!l)ral 

 keel. Erout lobe of plastron broader than hind lobe ; intergular 

 shield sliorter than its distaneo from the abdominals ; suture between 

 the latter shields usually longer than tliat l)etwcen the pectorals. 

 Head extremely large, covered with numerous small shields ; mental 

 barbels short, shorter than the diameter of the eye. Uniform brown 

 above ; ])lastron brown, bordered with yellow all round ; bridge and 

 lower surtace of marginals yellow ; a broad yellow band covers the 

 labial and tympanic regions. 



Length of shell 30 centim. 



Northern Brazil, Guianas, Ycnezuela. 



a. Ad., stffd. Tara. II. W. Bates, Esq. [C.]. (Type 



of //. ranicejjs.) 

 h, c. Ad., stffd. Surinam. 



d. Ilgr., stffd. Veuezucla. Sir llawson Rawson [P.]. 



e. Yg., spin ? (Type of //. vmciduta.) 



f. Ad., skel. ? 



5. HYDRASPIS*. 



Chelodina, part., Fitdng. N. Class. Rept. p. G (1820). 



Hydraspis, part., Bell, Zool. Journ. ni. p. oil (1828); Gi-a)/, Syn. 



"liept. p. Sd (1831), and Cat. Turf. p. .38 (1844), and Cut. Sh. 



Ilept. i. p. 54 (1855), and Suppl. p. 73 (1870). 

 Ilhiueun'S, part., Wai/lcr, Sijst. Am ph. p. 134 (J 830). 

 Phrynops, Wayler, I. c. p. 135; Orai/, Cat. Turt. p. 41. 

 Platemvs, part., Diim. c^- Bibr. ii. p. 404 (1835) ; StraucJi, Chelofi. 



Stud. p. 45 (1802). 

 Spatulemys, Gray, Ann. e^'- May. N. H. (4) x. p. 4G3 (1873). 

 Mesoclemoiys, Gray, I. c. (4) xi. p. 305 (1&73). 



Neural plates present, six in number ; nuchal shield present, mar- 

 ginal. Plastron large, with a very strong axillary and moderately 

 strong inguinal buttresses, the latter anchylosed to the fifth costal 

 plate. A parieto-squamosal arch ; parietals more or less expanded 

 superiorly. Jaws moderately strong, without alveolar ridges. Chin 

 ■with a pair of dermal appendages, or barbels. Digits entirely 

 ■webbed. 



South America. 



The following characters apply to all the species : — 

 Carapace much depressed, smooth in the adult ; vertebrals very 

 broad in the young, broader than the costals, much narrower in 



* 1. Hydraspisl offmis. Gray, Cat. Tort. p. 41 (1844).— Brazil. 

 2. 'Phrynops hellil, Gi'ay, I. c. p. 41. — Hab. ? 



