1885.] Eocene Period of North America. 467 
lachrymal foramen and the unossified symphysis mandibuli. 
Among Lemuridz its dental formula agrees only with the Indri- 
sinz, which have, like Anaptomorphus, two premolars in each 
jaw. But no known Lemuridz possess interior lobes and cusps 
of all the premolars, so that in this respect, as in the number of 
its teeth, this genus resembles the higher monkeys, the Simiidz 
and Hominide more than any existing member of the family. Of 
these two groups the resemblance is to the Hominide in the 
small size of the canine teeth. It has, however, a number of 
resemblances to Tarsius, which is perhaps its nearest ally among 
the lemurs, although that genus has three premolars. One of 
these points is the anterior extension of the otic bulla, which is 
extensively overrun by the external pterygoid ala. A conse- 
quence of this arrangement is the external position of the fora- 
men ovale, just as is seen in Tarsius. Another point is the prob- 
ably inferior position of the foramen ovale. Though this part is 
broken away in the cranium of Anaptomorphus homunculus, the 
paroccipital process is preserved, and has the position seen in 
Tarsius, as distinguished from the Indrisine, Lemuride, Gala- 
ginz, etc. In this it also resembles the true Quadrumana. 
When we remember that the lower Quadrumana, the Hapalidz 
and the Cebide, have three premolar teeth, the resemblance of 
Anaptomorphus to the higher members of that order is more 
evident. The brain and its hemispheres are not at all smaller 
than those of the Tarsius, or of the typical lemurs of the present 
period. This is important in view of the very small brains of the 
flesh-eating and ungulate Mammalia of the Eocene period so far 
as yet known. In conclusion, there is no doubt but that the 
genus Anaptomorphus is the most simian lemur yet discovered, 
and probably represents the family from which the anthropoid 
monkeys and men were derived. Its discovery is an important 
addition to our knowledge of the phylogeny of man. 
The Anaptomorphus homunculus was nocturnal in its habits, 
and its food was probably like that of the smaller lemurs of 
Madagascar and the Malaysian islands. Its large orbits and large 
otic bullae indicate great acuteness of the senses of sight and 
hearing. Its size is a little less than that of the Tarsus spectrum. 
In Pelycodus we have a more decidedly insectivorous type of 
dentition in the lower jaw, although that of the upper jaw 
(Fig. 1) has a lemurine character. Enough of the poste- 
