(Alcock, 1895)
In the younger stage, the carapace is not very convex, while, in the full-grown stage, the dorsal surface is markedly convex and the lateral surface on either side of the cardiac region is remarkably depressed. The postfrontal portion is so convex that its frontal margin is found deflected and can scarcely be detected in dorsal view. And the tubercles of the carapace of such adult specimens as this, are found growing more thickly than those of the younger ones. (Sakai, 1965)
Type locality: Pedro Shoal, India.
Range: Amirante Islands (Rathbun, 1911); India - Pedro Shoal (Alcock, 1895b); Japan - Sagami Bay, Kii Peninsula and Tosa Bay (Sakai, 1965b), Sagami Bay, Kii Nagashima, Kii Minabe and Tosa Bay (Sakai, 1976a).