1913.] N. Annandale : Tortoises 0/ Chota Nagpur. 67 



2. Amphibious species with a unicarinate carapace, with 



webbed digits but without a temporal a.xch,=Geoemyda, 

 Boulenger [QrSiy), =Heosemys, Stejneger. , 



3. Terrestrial species with a tricarinate carapace, with the 



digits hardly webbed and the hind feet club-shaped ; the 

 temporal arch present or absent, =C/2a^7Mssm, Theobald. 



The only other Oriental species [G. spengleri (Gmelin)] belongs 

 to the first of these groups. There is some doubt as to the hmits 

 of its range, but it is supposed to be distributed over an area ex- 

 tending from Sumatra to Japan. The Indian species of this group 

 have their head-quarters in India south of the Indo-Gangetic plain, 

 but a race of one of them is found in Burma. Those of the second 

 group are Burmese and in two out of three instances also occur in 

 the Malay Peninsula. One of these two species is also found in 

 Siam and Indo-China, the other in Sumatra and Borneo. The 

 species of the third group are found in the Indian Peninsula and 

 in Assam. A fossil form allied to them but perhaps specifically 

 distinct is described by Lydekker from the Pliocene of the SiwaUk 

 Hills under the name Nicoria tricar inata var. sivalensis {Journ. As. 

 Soc. Bengal, 1889, p. 333, fig- 2). 



The American species assigned to Nicoria by Mr. Boulenger, 

 and to Geoemvda {s.s.) by some recent writers, differ from the 

 Oriental ones in having only a single keel on the carapace and at 

 the same time possessing a complete bony temporal arch. 



Geoemyda trijuga (Schweigg.). 

 I. Forma typica. 



Testudo trijuga, Schweigg., Prodromus, p. 41 (1814); Boulenger 

 {Nicoria), Cat. Chel. Brit. Mus., p. 121 and Fauna Brit. Ind. 

 Rept., p. 27; Siebenrock [Geoemyda), Synops. Schildkroten, 



p. 495. 



Emys trijuga var. madraspatana, Anderson, Anat. Zool. Res. Yun- 

 nan, p. 729. 



The descriptions given by Boulenger and by Siebenrock serve 

 for the ready recognition of the species. I propose merely to lay 

 stress on sub-specific characters, on which the large series of speci- 

 mens at my disposal makes it possible to cast further light. 



Shell.— Car apsice broadly oval, usually of a warm brown colour, 

 but sometimes nearly black, not more than about 22 cm. long in 

 a straight line, moderately depressed, distinctly flattened on the 

 dorsal surface in adults (as well as young) of both sexes; keels 

 sometimes yellowish. Plastron moderately concave in the adult 

 male, brown or blackish, sometimes with a yellowish longitudinal 

 streak on each side. 



Head of young dull olivaceous with yellowish and greenish 

 streaks and veins (never very conspicuous) on the dorsal and 



