76 THE GENERAL ANATOMY OF THE LEMUROIDEA [SECT. A 



(? ossiculum Vesalii) above the pisiform carpal bone, as in Hylo- 

 bates. 



In the carpus the os centrale retains its original independence : 

 of the remaining bones, the metacarpals and proximal phalanges 

 are of equal length, the intermediate phalanges almost equal to 

 them, while the terminal phalanges are very short. The form 

 of the phalanges is of importance in regard to the ancestry of the 

 Lemurs. It is urged against the view that they are derived 

 from the Condylarthra (cf. Earle, Natural Science, May, 1897). 



The ossa innominata are elongated antero-posteriorly, i.e. in 

 the opposite direction to that in which their characteristic width 

 is shewn in Man. The iliac bones are long and narrow : the 

 pelvic brim (true pelvis) is nearly circular, thus contrasting with 

 many lower mammalian forms and approximating to the human 

 type. The symphysis barely extends beyond the pubic bones, 

 and the tubera ischii are smaller and less everted than in the 

 lower Anthropoidea. The thyroid foramen is of great size. 



The femur has a slender rectilinear shaft 1 , a small globular 

 head, and a short stout neck ; a third trochanter may occur. 

 At this level the shaft is " platymeric " with anteroposterior 

 flattening, while at its lower end, the bone appears as though 

 transversely compressed, when compared with the human femur. 

 The patella is also narrow, but the general conformation of the 

 knee-joint suggests a wide range of movement. There is a 

 sesamoid bone, which often remains attached to the femur, in the 

 outer head of the gastrocnemius muscle. The tibia is strongly 

 platycnemic 2 , and at the ankle the tibial malleolus is more 

 elongated and larger than that on the fibula. The tarsus is 

 flat, and the heel (os calcis) is prominent ; the os calcis is elongated 

 in some varieties (ex. gr. Galago) but not in Lemur (cf. infra 

 Tarsius). The first metatarsal bone bears so large a tubercle 



1 In the giant extinct Lemurs known as Megaladapis madagascariensis and 

 M. insignis, there is a curious flattening of the shaft, seen in both the humerus 

 and femur, as though pressure had been applied in the sagittal direction. The 

 specimens in the collections at S. Kensington and Vienna present these characters. 



a The tibial flattening to which this appearance is due, appears most markedly 

 in Lemurs, such as Galago, which have adopted a saltatory mode of progression. 

 This has been pointed out by M. Vallois in an admirable memoir (Bull, de la Soc. 

 (VAnth.de Paris, 1912, 3—4, p. 281). 



