OCR Text |
Show 992 MESSRS. B. C. A. WIN DUE AND F. G. PARSONS ON [Dec. 19, Family ORYCTEROPODIDCE. 35. Oryeteropus capensis. (Galton, VIII.) 36. „ „ (Humphry, IX.) 37. „ „ (Cuvier & Laurillard, XVII.) Ectogluteus (Gluteus maximus) and Gaudo-femoralis (Agitator caudce).-In the Bradypodidce the ectogluteus rises by fascia from the sacral and caudal spines ; according to some authors from the crest of the ilium also. As its origin is fascial, there is clearly considerable scope for diversity of opinion and description on this point. The insertion is into the shaft of the femur from just below the great trochanter to the middle or rather lower. No separate caudo-f em oralis has been described in these animals, except in Cuvier & Laurillard's specimen (6), in which it was very small. It seems quite probable that, in the other specimens of which descriptions exist, it is fused with the ectogluteus. This hypothesis is supported to a certain extent by the fact that in our specimen of Cholcepus (8) the muscle had a double insertion, the anterior fibres passing to just below* the great trochanter, thus obtaining the normal insertion of the ectogluteus in mammals, whilst the posterior fibres reached the middle and lower thirds of the femur. Among the Myrmecophagidce the ectogluteus and caudo-femoralis can usually be separated from one another, the former passing to the upper part of the femur and to the fascia lata, the latter to the lower part of the bone. This was certainly the case in Mgrmeco-phaga (11) and Tamandua (14, 16) and, to a less extent, in Cgclo-thurus (21), though most of the dissectors of this animal do not seem to have recognized the caudo-femoralis as a separate muscle. In the Dasypodidce and Manidce both the ectogluteus and caudo-femoralis are present, though usually closely united. In Chlamydophorus (28 a) the latter rose separately from the sphaeroma end of the lower sphaeroma support. In the Orycteropodidce the ectogluteus is inserted into just below the middle of the femur, and the caudo-femoralis into the lower end (37). Tensor fascice femoris aud ilio-tibialis (Sartorius).-In the Bradypodidce the ilio-tibialis is a well-marked muscle rising from the crest of the ilium and passing to the inner side of the head of the tibia. This applies to Bradypus (1. 4, 5, 6) and Cholcepus (8, 9). The muscular fibres rising external to this and in the same plane, instead of going to the fascia lata, accompany the ectogluteus to the outer surface of the shaft of the femur, but we are of opinion that they represent the tensor fascia1 femoris. In the Myrmecophagidce the ilio-tibialis is distinct and has the human attachments in Myrmecophaga (11) and Cyclothurus (17,21). In Tamandua (14) and Cyclothurus (20) it rises from the tendon of the psoas magnus or parvus. The tensor fascia? femoris is inseparable from the ectogluteus. In the Dasypodidce both muscles are present, but whereas the ilio-tibialis is a delicate muscle in Dasypus (22, 23, 24), it is thick and fleshy in Chlamydophorus |