Mr Apple'on, The Oluteil Region of Tarsius spectrum 467 



A thicker band of musculature forms its cephalad margin and 

 this has a special attachment to the 3rd trochanter by a small 

 tendon. Supplied by the superior (cephalad) gluteal nerve, it is 

 tbus distinguishable from the superficial gluteus muscle which 

 forms the hinder part of the muscle sheet and is supplied by the 

 inferior (caudad) gluteal nerve. The latter nerve reaches the hinder 

 edge of the muscle from behind the gluteus medius and enters its 

 deep surface. 



The cephalad gluteal nerve enters the deep surface of the tensor 

 fasciae latae after passing through the gluteus minimus. 



A complete deficiency of muscular tissue occurs behind the 

 tensor fasciae latae, a thick fascia only being present; and through 

 this the fibres of the superficial gluteus gain attachment to the 

 3rd trochanter. In front of the tensor fasciae latae the fascia lata 

 of the thigh is thinner than is the case in those numerous Mam- 

 malia where it receives the pull of the " tensor" muscle. This muscle 

 in fact acts in Tarsius as a flexor and rotator of the thigh on the 

 trunk, and not as an accessory extensor of the knee (which occurs 

 in the cursorial groups, e.g. Artiodactyla and Carnivora). 



Our description differs from that of Burmeister who states that 

 the tensor fasciae latae of Tarsius loses itself below in the fascia 

 lata. He mentions no tendinous attachment to the 3rd trochanter. 

 The gluteus medius and gluteus minimus are described by 

 Burmeister. They are little larger than in Tupaia (Table I)*. 



The femorococcygeus muscle claims our next attention. 



Burmeister evidently saw this muscle, but, erroneously, as we 

 think, described it as a "pyriformis" muscle; moreover, he ap- 

 parently regarded the caudofemoraUs as a second or deep pyri- 

 formis. These two muscles in Tarsius so closely resemble the muscles 

 described by I.eche in Tupaia, and are still more hke the muscles 

 of Lentur, that we cannot regard them as different structures. 

 Nerve supply is also similar in all these cases. A representative of 

 the femorococcygeus is even found in the anthropoid apes, sup- 

 plied by a branch from the nerve to biceps (Orang): and these 

 animals possess a separate pyriformis homologous with the human 



one. 



The femorococcygeus of Tarsius arises from the deep aspect of 

 the transverse processes of the 1st, 2nd, and 3rd caudal vertebrae 

 and from the intervening intertransverse ligaments. Its origin is 

 therefore quite distinct from that of the superficial gluteus. Below 

 the tail and immediately medial to its place of origin is situated 

 the sacrococcygeus; and it passes out from under cover of the 

 intertransversarius caudae (of Burmeister) and dorsal caudal 



* In Macropus the gluteus medius is, compared with the rectus femoris, twice 

 as large as in Tarsius (data by Haughton, Pr. R. Ir. Acad. ix). In cursonals it is 

 also much increased in size. 



