4, RHINEMYS.—). HYDRASPIS. 219 
Platemys nasuta, Strauch, Chelon. Stud. pp. 47 & 160 (1862). 
raniceps, Strauch, l. c. p. 47. 
Hydraspis maculata, Gray, Ann. § Mag. N. H. (4) xi. p. 3805 
(1878). 
Carapace much depressed, with at least a trace of a vertebral 
keel. Front lobe of plastron broader than hind lobe; intergular 
shield shorter than its distance from the abdominals ; suture between 
the latter shields usually longer than that between the pectorals. 
Head extremely large, covered with numerous small shields; mental 
barbels short, shorter than the diameter of the eye. Uniform brown 
above ; plastron brown, bordered with yellow all round; bridge and 
lower surface of marginals yellow ; a broad yellow band covers the 
labial and tympanic regions. 
Length of shell 30 centim. 
Northern Brazil, Guianas, Venezuela. 
a, Ad., stffd. Para. H. W. Bates, Esq.[C.]. (Type 
of H, raniceps.) 
b, c. Ad., stffd. Surinam. 
d. Her., stffd. Venezuela, Sir Rawson Rawson [P.]. 
e. Yg., spit. Pp (Type of LL, maculata.) 
f. Ad., skel. —-? 
5. HYDRASPIS *. 
Chelodina, part., Fitzing. N. Class. Rept. p. 6 (1826). 
Hydraspis, part., Bell, Zool. Journ. ii. p. 511 (1828); Gray, Syn. 
Rept. p. 39 (1881), and Cat. Tort. p. 38 (1844), and Cat. Sh. 
Rept. 1. p. 54 (1855), and Suppl. p. 78 (1870), 
Rhinemys, part., Wagler, Syst. Amph. p. 134 (1830). 
Phrynops, Wagler, l. e. p. 155; Gray, Cat. Tort. p. 41. 
Platemys, part., Dum. § Bibr. ii. p. 404 (1885) ; Strauch, Chelon. 
Stud. p. 45 (1862). 
Spatulemys, Gray, Ann. § Mag. N. H. (4) x. p. 463 (1878). 
Mesoclemmys, Gray, /. c. (4) x1. p. 805 (1873). 
Neural plates present, six innumber; 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. Hydraspis? affinis, Gray, Cat. Tort. p. 41 (1844).—Brazil. 
2, Phrynops beilii, Gray, l. ¢. p. 41.—Hab, ? 
