784 MAMMALIA, 
spheres are but slightly convoluted, and do not completely 
overlap the cerebellum (except in Indrisinz); the middle 
or transverse portion of the colon is almost always folded 
or convoluted on itself; there may be abdominal and 
inguinal as well as pectoral mammz ; the uterus is bicor- 
nuate; the urethra perforates the clitoris (except in 
Chiromys); the placenta is diffuse and non-deciduate except 
in Zuarsius, where it is metadiscoidal and deciduate. 
Among other features we may note that the Lemurs are 
plantigrade and usually pentadactyl; the tail (sometimes 
reduced) is never prehensile; the mandibles are often 
unfused at the junction; in the Madagascar forms the 
tympanic remains a half-ring within the bulla which is 
due to the periotic; the carpus has a centrale usually 
free ; there is a large cecum without a vermiform appendix ; 
there are often retia mirabilia on some of the arteries and 
veins. 
The lemurs are small, furry quadrupeds, with fox-like 
faces but the general appearance of monkeys. Most are 
nocturnal, all arboreal. They feed on fruits and leaves, 
on eggs and small animals. Most are loud-voiced. They 
are usually uniparous. 
A. Madagascar Lemurs, with the tympanic annulus free in the bulla. 
Family Lemurinz, with long faces. Some have interesting tufts of 
vibrissze on the forearm, and a strange forearm gland, with spines 
in the male. Family Indrisine, with short faces, cerebrum 
covering cerebellum. Family Chiromyine, with one type 
Chiromys, the Aye-Aye, highly specialised, e.g. with very long 
slender third finger, with a flat nail on the thumb only, with 
1113 
om) 
rodent-like permanent incisors ( 
1003 
, with inguinal mamme. 
B. Ethiopian and Oriental Lemurs, with the tympanic sharing in 
making the bulla, 
Family Galagine, with one type Gadago, with elongated calcaneum 
and navicular. It occurs right across Africa. Family Lorisine. 
Asiatic and African. 
C. The aberrant Indo-Malayan Zars¢us, with many peculiarities, e.g. 
the orbit communicates with the temporal fossa only by a fissure, 
the upper incisors are close together, the calcaneum and navicular 
are greatly elongated like the calcaneum and astragalus in the 
frog, the placenta is metadiscoidal and deciduate as in monkeys, 
The lemurs are interesting, both because they link the Anthropoidea 
to lower Mammals, and because of their distribution. In Eocene. 
