4, CYCLODERMA.—5. EMYDA. 267 
a, Ad., shell. Zambezi. Dr. Livingtone [P.]. (Type of 
Aspidochelys livingstoni.) 
6, Skull, hyoid, & foot. Zambezi. Sir J. Kirk [P.]. 
(From the first Livingstone Expedition.) 
2. Cycloderma aubryi. 
ea aubryi, 4. Dum. Rev. et Mag. de Zool. viii. p. 374, pl. xx. 
856). 
Heptathyra aubryi, Coupe, Proc. Ac. Philad. 1859, p. 294; Gray, 
Suppl. Cat. Sh, Rept. i. p. 93 (1870). 
Cycloderma aubryi, A. Dum. Arch. Mus. x. p. 166 (1860); Peters, 
Mon. Berl. Ac. 1876, p. 117, pl. —. 
Heptathyra frenata, part., Gray, Proc. Zool. Soc, 1864, p. 93, figs. 
Differs from the preceding in the broader interorbital region, 
which measures at least two thirds the diameter of the orbit; and 
in the larger plastral callosities, especially the entoplastral, which, 
instead of being by far the smallest of all, is the largest next to the 
hyo-hypoplastral and subcircular in shape; hyo-hypoplastral callo- 
sities 1n contact on the median line. Brown above; young orange, 
with a few black spots and a black vertebral line on the body, and 
three black streaks along the head and neck. 
Length of dorsal disk 45 centim. 
Gaboon and Ogowai. 
a, Ad., stffd. Gaboon. M. Du Chaillu [C.]. 
b. Ad., shell. Gaboon, M. Du Chaillu ted 
ce. Ad., skel., incomplete. Gaboon. {M. Du Chaillu | C. |. 
5. EMYDA. 
Trionyx, part., Geoffr. Ann. Mus, xiv. p. 1 (1809) ; Schweigg. Prodr. 
p. 18 (1814) ; Fitzing. Syst. Rept. p. 7 (1826). 
Trionyx, Wagl. Syst. Amph. p. 134 (1830). 
Emyda, Gray, Syn. Rept. p. 49 (1831), and Cat. Tort. p. 46 (1844), 
and Sh. Rept. i. p. 63 (1855); Strauch, Chelon. Stud. p. 56 
(1862) ; Giinth. Rept. Brit, Ind. p. 44 (1864); Gray, Suppl. Cat. 
Sh. Rept. i. p. 117 (1870), and Proc. Zool. Soc. 1873, p. 71. 
Cryptopus, part., Dum. § Bibr. ii. p. 499 (1835). 
Potamochelys, part., Gray, Proc. Zool. Soc. 1864, p. 85, and Suppl. 
Cat. Sh. Rept. p. 104, and Ann. & Mag. N. H. (4) x. p. 388 
(1872). 
Nuchal notched at each outer end, which underlies the first 
costal plate; dorsal shield large, with a series of bony plates in the 
posterior cutaneous border and a prenuchal marginal bony plate ; 
neural plates well developed, seven or eight in number, forming a. 
continuous series; eighth pair of costals large in the adult, and, 
like the penultimate, forming a median suture. Plastron with a 
cutaneous femoral valve, under which the hind limb may be con- 
cealed; hyoplastron coossified with hypoplastron ; seven plastral 
callosities (in the adult). Bony choanze between the orbits ; jaws 
strong ; postorbital arch moderate, much narrower than the diameter 
