6. PLATEMYS,. 297 
1. Platemys spixii. 
Emys depressa (zon Merr.), Spix, Test. Bras. p. 4, pl. ii. fig. 2 
(1824). 
Platemys spixii, Dum. & Bibr. ii. p. 409 (1835); Strauch, Chelon. 
Stud. p. 152 (1862), and Verth. Schildkr. p. 114 (1865). 
Hydraspis spixii, Gray, Cat. Tort. p. 39 (1844), and Sh. Rept. 1. 
p- 54 (1855), 
Acanthochelys spixii, Gray, Ann. § Mag. N. H. (4) xi. p. 805 (1873). 
Carapace grooved along the vertebral line, the shields with con- 
centric and radiating strie ; nuchal shield twice as long as broad ; 
first and fifth vertebrals very large, second, third, and fourth about 
as long as broad in the adult. Plastron large, four times as long 
as the width of the bridge, angularly notched behind in the half- 
grown, very feebly in the adult ; proportions of the plastral shields 
very variable. Skin of upper surface of head divided into numerous 
small irregular shields ; snout extremely short, very feebly project- 
ing ; width of the parietal bones above a little more than the dia- 
meter of the orbit ; mental barbels very small. Upper surface of 
neck with large, erect, conical, soft tubercles. Limbs moderately 
webbed, covered with squarish scales; a fringe of enlarged scales 
along the outer edge of the fore limb; a much developed, com- 
pressed, crescentic process on the inner side of the leg, formed by 
three very large tubercles. Shell dark brown or black above and 
below; head and limbs uniform olive-brown above, lighter olive 
inferiorly. 
Length of shell 16 centim. 
Brazil. 
a, Q,, stitd. Brazil. 
b. Hegr., spir. San Lorenzo, Rio Grande do Sul, Dr. v. Ihering [C. ]. 
2. Platemys platycephala. 
Testudo platycephala, Schneid. Schrift. Berl. Naturf, Fr. x, p. 259, 
pl. vu. (1792). 
—— planiceps, Schoepff, Test. p. 115, pl. xxvii. (1792). 
martinella, Daud. Rept. 11. p. 344 (1803). 
Emys planiceps, Schweigg. Prodr. p. 34 (1814). 
canaliculata, Spix, Test. Bras. p. 10, pl. viii. (1824). 
Platemys canaliculata, Wagl. Syst. Amph. pl. iv. figs. 1-26 (1830). 
Hydraspis planiceps, Gray, Syn. Rept. p. 40 (1831), and Cat. Tort. 
p. 39 (1844). 
Platemys martinella, Dum. § Bibr. ii. p. 407 (1835). 
P Hydraspis spixii, Tschudi, Faun. Per., Herp. p. 22 (1845). 
Platemys planiceps, Gray, Cat. Sh. Rept. i. p. 54 (1855), and Suppl. 
p. 75 (1870) ; Strauch, Verth. Schildkr, p. 114 (1865). 
Carapace very much depressed, deeply grooved along the vertebral 
region, on each side of which is an obtuse longitudinal keel ; shields 
feebly striated concentrically in the adult; nuchal narrow ; fourth 
and fifth vertebrals small. Plastron large, its length about thrice 
and a half the width of the bridge; axillary and inguinal shields 
R 
