1. TRIONYX. 255 
Stud. p. 175 (1862), and Verth. Schildkr. p, 126 (1865); Boettg. 
Ber, Senck. Ges. 1879-80, p. 208 (1880). 
Trionyx niloticus, Gray, Syn. Rept. p. 46 (1831), and Cat. Sh. Rept. 
i. p. 68 (1855). 
Gymnopus egyptiacus, Dum. § Bibr. ii. p. 484 (1835). 
Trionyx labiatus, Bell, Test. pls. — (1837). 
Tyrse nilotica, Gray, Cat. Tort. p. 48 (1844), and Proc. Zool, Soc. 
1864, p. 88, and Suppl. Cat. Sh. Rept. i. p. 108 (1870), and Ann. 
§ Mag. N. H. (4) x1. p. 470 (1873). 
Trionyx mortoni, Hallow. Proc. Ac. Philad. 1844, p. 120. 
Aspidonectes aspilus, Cope, Proc. Ac. Philad. 1859, p. 295. 
Fordia africana, Gray, Proc. Zool. Soc. 1869, p. 219, and Suppl. Cat. 
Sh, Rept. i. p. 100, and Proc. Zool. Soc. 1873, p. 43, figs. 
Trionyx triunguis, Peters, Mon. Berl. Ac. 1876, p. 117. 
Costal plates eight pairs, the last well developed and in contact 
throughout on the median line; a single neural between the first 
pair of costals; dorsal plates coarsely pitted and vermiculate. Dor- 
sal skin of young with longitudinal ridges of small tubercles. 
Kpiplastra widely separated, the anterior branch short; entoplas- 
tron forming a right or acute angle; plastral callosities well deve- 
loped in the adult, hyo-hypoplastral and xiphiplastral, and coarsely 
sculptured like the carapace. Head small; snout (on the skull) 
much longer than the diameter of the orbit; interorbital space, in 
the adult, at least as broad as the nasal fossa; postorbital arch not 
half the diameter of the orbit; mandible without symphysial ridge, 
its width at the symphysis equalling or exceeding the diameter of 
the orbit. Olive above, closely spotted and speckled with whitish 
in the young; throat and lower surface of shell with round white 
spots separated by a dark network ; adult more uniform, 
Length of dorsal disk 80 centim. 
Africa (Nile, Congo, Senegal, and intermediate water-systems) 
and Syria. 
a,b. Ad. & yg., stffd. Egypt. Dr. T. Christie [P.]. 
ec. Ad., stffd. Egypt. T. Thornton, Esq. [ P.]. 
d. Her., stffd. Egypt. Zoological Society. 
e. Her., skel. Keypt. Dr. Riippell (C.]. 
J,g. Ad., stffd., skull sepa- Chartoum. Consul Petherick [C.]. 
rate. (Types of Fordia africana.) 
h. Ye., spir. Chartoum. Consul Petherick [C. ]. 
a. Yo., spir. Nile. Zoological Society. 
k, Yg., spir Gambia. Dr. Bailie [C.]. 
1. Ad., stffd. Gaboon. M. Du Chaillu [C.}, 
m-p. Yg., spit. Lower Congo. M. A. Linden [C.]. 
q-t. Yg., spir. W. Africa, Dr. Baikie [C.]. 
u. Yg., Spit. W. Africa, G. Malcolm, Esq. [P.]. 
v. Ad., skull & hyoid bones. W. Africa. J.J. Monteiro, Esq. [ P.1]. 
w. Her., skel. ? 
