1869. | DR. J. E. GRAY ON THE TORTOISES. 207 
Emys decussata, Bell; Gray, Cat. Shield Rept. in B. M. t. 36. 
f. 2 (skull). 
Skull in British Museum. The internal nostrils subanterior, be- 
tween the converging alveolar plates; lower jaw with a short 
groove. 
20. TRACHEMYs. 
TRACHEMYS HOLBROOKII. 
Trachemys holbrookii, Gray, Aun. & Mag. N. H. xii. p. 181. 
Limys cumberlandensis, Holbrook. 
Trachemys holbrookii. 
Skeleton (in separate bones) in the British Museum, prepared by 
Dr. Giinther. Skull ovate, solid, crown quite flat, sides of face 
shelving outwards; nose rather produced beyond the mouth; orbit 
very large, lateral, subsuperior, upper hinder edge narrow; zygo- 
matic arch very broad, convex ; tympanic cavity subcircular. The 
edge of the jaws swollen, convex, labial edge rather arched, entire 
in front. The palate flat; internal nostrils large, subanterior, with 
an elongated broad slight concavity behind them. The alveolar 
