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Show 1873.] DR. J. E. GRAY ON THE TRIONYCHlDcE. 71 Cyclanosteus (Cyclanorbis) petersii, Gray, P. Z. S. 1852, p. 135 ; Ann. & Mag. N . H. 1855, xv. p. 69. Cyclanosteus petersii, Gray, Cat. Sh. Rept. p. 64, t. 29 (shield) ; P. Z. S. 1860, p. 315. Cyclanosteus senegalensis, Gray, P. Z. S. 1864, p. 95, figs. 16-18 (skull) ; P. Z. S. 1865, p. 427 ; Suppl. Cat. Sh. Rept. p. 112, fig. 37 (skull), fig. 38 (sternum). Hab. Rivers of Western Africa ; Gambia, Senegal. The different specimens of this species have the sternal callosities differing in shape and proportion as regards each other. Thus the specimen figured as C. petersii, Cat. Sh. Rept. t. 29 (the skeleton in the Museum), has the central odd callosity half the width of the pair of bones before it, and the hinder pair of callosities small and roundish. A second specimen in the Museum has the central odd callosity more than two thirds the width of the pair of callosities before it; and the hinder pair of callosities is ovate, nearly the whole length of the bones on which they are situated, and are diverging from each other. This specimen has an additional callosity on the right side of the odd callosity. There is another specimen in the Museum which has this additional callosity on each side of the central callosity (see Suppl. Cat. Sh. Rept. p. 113, fig. 38). There is a third specimen, which differs in the odd central callosity being transverse and subtriangular, and nearly as broad as the pair of bones before it (see Suppl. Cat. Sh. Rept. p. 113, fig. 38a, where these callosities are figured). In this specimen the hinder callosities are entirely wanting or, rather, undeveloped. ** The dorsal disk with a regular series of marginal bones on the hinder lateral edge, and with a single marginal bone in front, all callous and rugose externally.-India. EMYDA. Emyda, Gray, Suppl. Cat. Sh. Rept. p. 117, and fig. 24, p. 105 (skull, as Pelochelys stellata); Ann. & Mag. Nat. Hist. 1872,x.p. 340. Lower jaw with a narrow edge, and shelving internally in front, with a wide concave alveolar edge on the sides. The dorsal disk with a central bone, callous on the outer side in the middle of the front margin, rather large and separate from but received into a notch in the front edge of the odd bone of the dorsal disk. A regular series of bones, which are callous externally on the hinder lateral margin. Sternum with seven callosities-one pair anterior, one pair lateral, and one pair posterior, and one single central callosity, which is generally of a roundish form. 1. EMYDA PUNCTATA. Anal callosities oval, oblique, inner edge of each rounded. Testudo punctata, Lacep. Qu. O. t. 171. Testudo scabra, Latr. Rept. i. p. 194. Testudo dura, B. Hamilton, icon. ined. |