6 MACACUS. 
Another specimen of a fossil tooth of the Macacus cocenus 
had been previously discovered, 1838, m the same stratum 
and locality as the fossil above described. It was sub- 
mitted to my inspection by Mr. Lyell, who has commu- 
nicated the result of my comparisons in the ‘“ Annals of 
Natural History,” for November 1839, proving it, likewise, 
to be the molar of a Monkey of the genus Macacus, thus 
constituting at once the first terrestrial mammal which 
had been found in the London Clay, and the first Quadru- 
manous animal hitherto discovered in any country in tertiary 
strata so old as the Eocene period. 
The specimen in question consists of the crown and 
one fang of the first true molar tooth, and is marked 
m, 1, in the cuts figs. 1 and 3. The series of teeth in the 
recent lower jaw, figs. 2 and 4, figured for comparison, 1s 
divided into two incisors, marked 7, one laniary, or canine, 
marked /, two premolars, or false molars, (called bicuspides 
in human anatomy,) p, and three molars or true molars, 
of which the analogues of the fossil teeth are marked re- 
spectively m, 1, and m, 3. The crown of the false molar 
of the fossil Macacus, (am, 1, figs. 1 and 3,) presented four 
tubercles, arranged in two transverse pairs, the anterior pair 
being the highest; there was, also, a very small ridge 
across the anterior, and another across the posterior part 
of the crown. The latter is placed between, and connects 
together the two posterior tubercles. The fangs were 
two in number, strong, and divergent: the tooth had be- 
longed to an animal that had passed its maturity, the tu- 
bercles having been worn at their summits, and the posterior 
concavity having been smoothly deepened by attrition. 
It differed from the corresponding tooth in the existing 
Macacques, in having the ridge along the base of the 
forepart of the crown, and by being relatively narrower 
