ON TOLYPEUTES TRICINCTUS. 433 
inches 
From tip of nose to base of tail.......... 12°55 
NE BOS Pn eae REE eR, Sarai 2°8 
PMIEMNE CUE GRIDS 9 ys a ong: cin oe Vl assd 09 8 o 9's is 21 
from which it is evident, on comparison with the table of measure- 
ments of the specimens in the national collection given below, that the 
individual was not adult, but fairly grown. 
The differences between the two known species of the genus Toly- 
peutes are so slight that it may be worth while referring to them before 
going further. It is to M. Geoffroy Saint-Hilaire that we owe the 
discovery of the second species (7. conwrus); and his most lucid 
description is to be found in the “ Comptes Rendus” for 1847.* 
Therein the history of the Apar is fully expounded, references being 
given to all previous important accounts of the animal. 
Tt is in the central portion of the cephalic shield that the most 
important peculiarities are to be seen. The marginal plates of the 
posterior two-thirds of this shield form a regular series, and enclose 
other larger plates—namely, a posterior median plate, followed ante- 
riorly in T. tricinctus by a pair of plates, in front of which, again, is Page 223. 
another smaller pair. 
In T. conurus the posterior median plate is followed by a single 
larger plate, and that by a pair of plates the transverse breadth of 
“which is greater than that of the second median plate behind and in 
contact with it. In fig. 1 (p. 434), a and 6 exhibit these features, as well 
as their effect in causing the characteristic difference in the general 
shape of the cephalic shield of the two species—that in T. tricinctus being 
triangular, with its greatest breadth opposite the posterior of the pairs 
of plates, that in T. conurus being oval, with its greatest breadth op- 
posite the single pair of plates. 
On referring to the beautiful illustrations given by Dr. Maurie of 
the animal dissected by him,} the cephalic shield of which is here re- 
produced in outline (fig. 1 [p. 434], c), it is evident that it does not corre- 
spond with either of those above described ; and I may mention that 
there is a skin in the national collection (Brit. Mus. spec. 140 a) which 
agrees with it. In these the posterior median plate is followed by a 
second larger median plate, asin T. conurus, and that, more forward, by 
a small median plate in association with two small lateral plates. The 
difference makes me feel justified in establishing a third species of 
Tolypeutes, based upon Dr. Murie’s figure, together with the skin in 
the national collection above referred to, for which I would suggest 
* Vol. xxiv. p. 572. 
t+ “Trans. Linn, Soc.” vol. xxx. pl. xxxi. fig. 3. 
2 F 
