784 MAMMALIA. 



spheres are but slightly convoluted, and do not completely 

 overlap the cerebellum (except in Indrisinae) ; 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 mammae ; the uterus is bicor- 

 nuate; the urethra perforates the clitoris (except in 

 Chiromys) ; the placenta is diffuse and non-deciduate except 

 in TarsiuS) 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 caecum 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 Lemurinse, with long faces. Some have interesting tufts of 



vibrissae on the forearm, and a strange forearm gland, with spines 

 in the male. Family Indrisinge, with short faces, cerebrum 

 covering cerebellum. Family Chiromyinae, 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 



rodent-like permanent incisors ( ), with inguinal mammae. 



B. Ethiopian and Oriental Lemurs, with the tympanic sharing in 



making the bulla. 



Family Galaginae, with one type Galago, with elongated calcaneum 

 and navicular. It occurs right across Africa. Family Lorisinae. 

 Asiatic and African. 



C. The aberrant Indo- Malayan Tarszus, 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 



