50 MR. J. C. GALTON ON DASYPUS SEXCINCTUS. 



lumbar vertebra, from the free edge of the tuberosity of the ilium, from the sacral 

 aponeurosis which covers the longitudinal caudal muscle and the gluteus medius, and 

 from the free superior edge of the ischial tuberosity. 



Its fibres converge towards the tbird (external) trochanter of the femur, into the 



external face of which process they are inserted, as well as into the ligament stretched 

 between this trochanter and the extremity of the ridge continued upwards from the 

 external condyle. 



Gluteus mediua. — A well-developed, but irregularly shaped muscle, arising from the 

 external free ridge or " crest " of the ilium, and from its posterior (or superior) fossa, 

 and from the metapophyses of the sacral vertebrae. The sacral and iliac element fuse at 

 the external or anterior free edge of the muscle, but enclose between them a kind of 

 cavity or sac, which is occupied by the pyriformis. That portion of the muscle 

 which arises from the sacrum is inserted into the posterior part of the summit of the 

 greater external trochanter of the femur, and partly into the posterior intertrochanteric 

 ridge, just external to the insertions of the gemelli and obturator externus. The factor 

 which takes origin from the ilium terminates through a strong tendon at the anterior 



part of the summit of the great trochanter, which tendon is joined, shortly before inser- 

 tion, by that of the pyriformis. 



Cuvier gives a good representation of the superficial portion of the muscle in two of 

 his plates 1 . 



The Gluteus minimus appears to be absent, and is, moreover, not figured bv Cuvier. 

 This muscle, according to Meckel 2 , is not differentiable from the gluteus medius in the 

 Sloth and Anteater. Eapp, on the other hand, found all these glutei in Myrmecophaga 



tamandua*. 



Pyriformis.— A flat muscle, of nearly uniform breadth, arises from the anterior half of 

 the posterior or superior margin of the oval foramen into which the great sciatic notch 



ted by the articulation of the spine as well as the tuberosity of the ischium with 



transverse processes of the last three sacral vertebra, the above-mentioned mai 



g formed by the free edge of the processes of the middle vertebra? of the sacrum. 



This muscle does not appear to have any origin from the concavity or inner face of 



5 



^acrum 



?> 



It is inserted into the summit of the great trochanter of the femur, bsing fused at its 



insertion with the strong terminal tendon of the inner layer of the gluteus medim. 



Cuvier indicates the origin of the pyriformis (<< pyramidal," or " sacro-trochanterien 

 in one of his plates'. The muscle appears to he separable into two portions, which 

 however, fuse again at its insertion. 



^According to Meckel •, it consists of two elements, and is of fair size in the Platypus 



Obturator externus.-ls a fan-shaped muscle, which takes origin from the whole of the 



"Z. X • f f t° " , f0ramen ' aUd " inSerted ^ a **»* ^ tendon into the 



to 7 n e f enC ^f' JUSt b6l0W the di S Ual fossa * ^e femur, and imme- 



diately anterior or inferior to the insertion of the gemelli. 



' PL 259. fig. 3, and pi. 2G0. * On cit n«l . r. ■ 



<Jp. at. p. 581. • Op. ct. p. 50. • PI. 259. fig. 8 . . op. cit. p. 683. 



