174 Proceedings of the Boyal Physical Society. 



by a separate branch from the superior gluteal nerve. The 

 superior gluteal nerve was derived from the 5th and 6th 

 lumbar nerves. On tracing back the separate branches to 

 the spinal nerves, it was found that the two middle pieces 

 of the muscle obtained their supply from the 5th and 6th 

 nerves about equally, while the supplies to the first piece 

 and the last were from the 5th lumbar nerve only. 



In various monkeys the gluteus minimus varies consider- 

 ably in its development and degree of subdivision. 



In the lemurs (2) it is much smaller than the other two 

 glutei. In the Galago crassicauclatus and G, Allenii it is 

 very short and small, arising only round the upper part of 

 the acetabulum, and resembles a gemellus. This probably 

 corresponds to the lowest division of the muscle in Hapale, 

 the rest possibly being fused with the medius. 



In the Tarsius there is a portion of the gluteal mass 

 which may belong either to medius or minimus, for Bur- 

 meister (10) described it as part of minimus, while Murie 

 and Mivart described it as part of medius. Beyond that 

 subdivision in Tarsius, there is none in the lemurs. Windle 

 does not indicate that there was any splitting of the muscle 

 in Midas, or in his specimen of Hajpale jacchus. There is no 

 splitting in Cynocephalus anuhis (7). In Macacios cynomolgios, 

 Cercopithecus sahaeus, and Cynocephalus maimon (9), minimus 

 is a feeble muscle, and its more anterior part suggests a 

 scansorius. In the chimpanzee (8) the muscle is separable 

 into three parts — an anterior, a posterior, and a third under 

 cover of the anterior. In the gorilla (8) there are two 

 portions, an anterior and a posterior. In man, gluteus 

 minimus is sometimes split into two, and occasionally the 

 superior gluteal nerve passes between the two parts (11). 



The scansorius was first observed in the chimpanzee, and 

 was named by Traill (12). It is not present as a distinct 

 muscle in any of the Lemuroidea (2), but the portion dis- 

 tinguished by Burmeister in the Tarsius may represent it. 

 It is well developed in Hapale penicillata (9), and is to 

 a considerable extent separate from the gluteus minimus, 

 as in Hapale jacchus. In Macacits cynomolgus, Ccrcopithecus 

 sabaeus, and Cynocephalus maimon, it appears only as the 



