? EQUUS ZEYLANIOUS. 
279 
Comparative Table of the more important Characters of the upper left P. M. 4 of (A) Hquus leptostylus, 
and the upper left M. I. of (B) the Wellawatta Horse, and (C) Z. caballus. 
(See Plate I.) 

Character 
No. 
wo 
Pillars 
a 

10 

(A) E leptostylus (upper left P. M. 4). 
(B) The Wellawatta Horse 
(upper left M. I.). 
(C) B. caballus 
(upper left M. I.). 

The anterior middle and outer folds are well developed 
and wide, each having a distinct vertical median 
furrow 
Anterior inner pillar very small and short, measures 
10 mm. in length and 5 mm. in width at the grinding 
surface 
Anterior inner pillar is not rounded, but irregularly 
triangular, with concave inner side in section 
Posterior inner pillar also very small and short, with 
perfectly rounded posterior border 
Neither of the pillars reaches the boundary of the tooth 
proper; the bays just anterior to the anterior 
pillar and posterior to the posterior pillar yielding 
a comparatively large surface for cement. 
Simple spur projects into bay between two inner 
pillars 
Anterior border of anterior crescent has one con- 
spicuous fold 
Posterior border of anterior crescent has one con- 
spicuous double fold and two rather feeble ones 
Anterior border of posterior crescent has one very 
conspicuous and two very feeble folds 
Posterior border of posterior crescent has one rather’ 
conspicuous single fold (the additional fold which 
appears in the original photograph and in the 
diagram is presumably only apparent, and is due to 
the foreshortening of a worn surface) 
Anterior horn of anterior crescent is wide and squarish, 
but not angular, it is directed 
Posterior horn of anterior crescent tending to pointed 
Anterior horn of posterior crescent is club-shaped and 
laterally directed. The apex is anterior. 
Posterior horn of posterior crescent points outwards 
and backwards 
Bay between anterior and posterior inner pillars 
widens towards its mouth 
Bay anterior to anterior inner pillar is angular 


Not quite s0 wide 
Longer in proportion to 
length of tooth than in 
(A). Length 11 mm. 
width 44 mm. 
Distinct concavity on. inner' 
side 
Rather small and_ short ; 
well rounded exterior 
border 
Much as in (A), but bay pos- 
terior to posterior pillar 
smaller (in proportion) 
than in (A) 
As in (A), but spur not so 
large in proportion to bay 
One conspicuous fold and 
one very feeble, one accen- 
tuated by uneven wear of 
the tooth 
Double fold highly conspic- 
uous, one well marked, 
one fairly well marked, 
and one very feeble fold 
As in (A) 
One fairly conspicuous single 
fold 
Wide and squarish ; points 
outwards and forwards 
Much as in (A) 
Crescentrie in shape. 
is posterior 
Points laterally 
Apex 
As in (A), but not so marked 
Bay is rounded 

Much as in (B) 
Longer in proportion to 
length of tooth than in (B). 
Length 11 mm.; width 
5 mm, 
Rounded 
Asin (B), but exterior border 
somewhat subangular 
As in (B), but bay posterior 
to posterior pillar not so 
deep as in (B) 
Spur extremely small; is 
accompanied by a small 
fold to the inner side 
As in (B), but minor fold very 
slight 
One very conspicuous single 
fold; one well-marked 
double fold; two well- 
marked single fold 
One highly conspicuous, one 
conspicuous, one very 
feeble, and two long gentle 
folds 
One conspicuous double fold 
Wide and tending to pointed. 
Points forwards and out- 
wards 
Rather more pointed 
As in (A), but less club- 
shaped 
Much as in (A) 
Bay narrows towards its 
mouth 
As in (B), but with squarish 
tendency. 
——— 
Note,—The numbers in column 2 correspond with the numbers in Plate I. 
16 
6(9)16 
