ON TOLYPEUTES TRICINCTUS. 435 
length of the head, on the right side of which it always lies when the 
animal is rolled up.* 
I can find no important differences among the species in the ante- 
rior portion of the carapace. In the three free transverse semizones | 
T. conurus and T. muriei agree, and differ from 7. tricinctus in that the 
terminal or marginal lateral scutes of each zone (which with the scute 
above on each side of each zone are less tubercnuiated than the rest, to 
reduce the friction when the animal rolls itself up) are more detached 
from the second scute, are more rounded, and are smaller propor- 
tionately. 
In the posterior moiety of the carapace of T. conurus and T. muriei 
fifteen, sixteen, seventeen, or eighteen rows of scutes can be counted 
along the middle line from before backwards if the marginal scutes are 
_ included in the numeration; in T. tricinctus I never find more than 
thirteen or fourteen rows. 
In T. tricinctus only there is a triangular area composed of small 
scutes, with its apex directed downwards, and basally in contact with 
the cephalic shield, which interpolates itself between the eye and ear 
on each side. 
The following measurements of the specimens of the different 
species in the national collection may prove of service in determining 
the proportions of each. They demonstrate that the head is decidedly 
_ shorter than the anterior moiety of the carapace in T. tricinctus, whilst 
“in T. conurus and T. muriei it is nearly always longer; that in T. tri- 
cinctus the head is more than half the length of the posterior moiety of 
the carapace, whilst in the two other species it is not so much as half 
that measurement. 
T. tri- | T. tri- | T. tri- | T. conu-| T. conu-| T. conu-| T. co- Yh ya 
cinctus. | cinctus. | cinctus. rus. rus. rus. |nurus.| muriei. | muriet. 
Sed ot: in. in. in. in. in. in. in. in. in. 
phalic shield 3 2°9 2°9 2°75 2°75 2°75 | 3 3:1 ? 
of an- 
terior shield 3-2 3°3 3°4 2°75 2°55 2°65 | 3-1 2°8 2°65 
h of pos- 
terior shield 5°8 5°75 5-7 5°5 5°75 5°8 6°75 6°3 6°3 
Length of tail 
(upper 
aspect). ? 2°25 2°25 2°2 2°2 2°2 2°5 ? ? 
M.49,| B.M. B.M. B.M. | B.M.52,| B.M.46,| B.M.| B.M. | Dr. Mu- 
, 12, 1. mo. 140 d.\no. 140 ¢.no. 140 2.|8 ki 
* Dr. Murie figures the tail on the left of the head (7. c.)—the photograph from 
which the drawing was made not having been reversed, most probably. 
2¥r2 
