TESTUDINID&. 49 
pages, so far as consistent with what appear to be the affinities of 
the various forms. But for the necessities of a serial arrangement, 
the genus Hmys, in many respects the least specialized, might be 
placed at the base of the family, with two diverging series of genera 
culminating in the Batagurs on the one hand and in the Land- 
Tortoises on the other. 
Synopsis of the Genera. 
I. Digits usually webbed, or with at least a slight rudiment of 
web, the median with three phalanges ; metacarpals elongate. 
A. Hexagonal neural plates short-sided in front. 
1. Alveolar surface of upper jaw broad, with one or two 
median ridges, 
a. Axillary and inguinal buttresses much developed, the 
former connected with or nearly reaching the first rib, 
the latter anchylosed between two costal plates (5th 
and 6th); entoplastron anterior to the humero-pectoral 
suture. 
a. Fourth vertebral shield elongate, embracing four or 
five neural bones .. 1. Kachuga, p. 51. 
B. Fourth vertebral shield not longer than third, embra- 
cing three neural bones. 
Choane between the eyes; alveolar surface of upper jaw with a 
single median ridge ........ .. 2. Callagur, p. 60. 
Choanze behind the level of the eyes; alveolar surface of upper jaw 
with two median ridges ; fore limb with four claws only. 
3. Batagur, p. 61. 
Choane behind the level of the eyes; alveolar surface of upper jaw 
with a single median ridge .... 4. Hardella, p. 63. 
6. Axillary and inguinal buttresses short or moderate. 
Choane behind the level of the eyes; inguinal buttress anchy- 
losed to the fifth (exceptionally sixth) costal plate; entoplastron 
anterior to the humero-pectoral suture. 
5. Morenia, p. 66. 
Choanz between the eyes; inguinal buttress anchylosed to the fifth 
costal plate ; entoplastron anterior to the humero-pectoral suture. 
6. Chrysemys, p. 69. 
Choane between the eyes; inguinal buttress anchylosed between 
the fifth and sixth costal plates; entoplastron intersected by the 
humero-pectoral suture........ 7. Ocadia, p. 85. 
