468 Mr Appleton, The Gluteal Eegioti of Tarsius spectrum 



musculature. It is inserted by muscular fibres along the outer side 

 of the back of the femur for four-sevenths of its total length, cover- 

 ing a broader area above, at the back of the great and 3rd tro- 

 chanters, than along the shaft. There is a delamination into strips 

 of muscle attached behind the 3rd trochanter, close to the centre 

 of rotation of the hip-joint; the hinder and larger part of the 

 muscle, attached to the femoral shaft, is quite distinct from the 

 remainder. 



The nerve-supply of the femorococcygeus is provided by a 

 special branch passing from the great sciatic nerve* caudad to 

 gluteus medius; the nerve enters it behind the great trochanter. 

 The femorococcygeus is superficial except at its insertion, where 

 the bulky vastus externus overlaps it. It covers the great sciatic 

 nerve; also the obturator internus and gemelh, quadratus femoris, 

 adductor magnus and caudofemorahs from above downwards. The 

 muscle is relatively smaller than in Lemur, and the insertion is 

 less extensive. It closely resembles the muscle of Simiidae, except 

 in being readily separable from the superficial gluteus. A further 

 difference from Simiidae hes in its (primitive) origin from coccygeal 

 vertebrae. In Simiidae its origin is" from the tuber ischii. 



The caudofemoralis muscle of Tarsius arises from the tuber 

 ischii cephalad to the biceps tendon. A flat muscular band, it 

 passes down to the middle of the thigh where it gains insertion to 

 the back of the femur, a rough line marking the place, for a distance 

 equal to one-fifth of the femoral length, equidistant from either end. 

 It IS immediately medial to the insertion of the femorococcygeus. 

 It receives its nerve supply from the nerve to the hamstring 

 muscles (from the great sciatic). 



It is situated in its whole length on the deep aspect of the 

 femorococcygeus, except when the great sciatic nerve intervenes 

 between them [v. Plate IV, fig. 2]. 



In Tupaia this muscle is a far thinner sheet, with tAvo places 

 of msertionf: (1) to the back of the shaft (one-fourth of the length 

 of the femur); (2) just proximally to the internal condyle. In 

 Lemur it is thin and the length of its insertion one-tenth of the 

 length of the femur. In Simiidae it is indistinguishable. 



The nerve to the hamstring muscles {i.e. to biceps, semi- 

 tendmosus and semimembranosus) passes deep to the 'caudo- 

 femoralis muscle. 



_ These nerve-relationships are characteristic of the muscle J also 

 m Tupaia among Insectivora, and in Lemur among Primates in 

 specimens I have dissected. Tbey, together with the attachments of 

 the caudofemorahs to bone, are sufiicient to establish the identity of 



* As also in Tupaia and Lemur. 



t Cf. the corresponding caudifemoralis of Reptilia—Gadow, lor. cit. 1882 

 J Cunningham's figure of the thigh of Phalangista shows (as the "ischiofemoral 

 muscle ) agreement m that animal also. ' Challenger' Report, \^^-2, yo\ v Plate III- 



