﻿I 



MURIE ON THE THREE-BANDED ARMADILLO, 103 



with by Mm in B. G-cinctus ; it was alluded to by Huxley^ as a differentiated muscle going 

 to the sesamoid. Galton^ in the same species of Armadillo, very clearly describes the 

 relations, course, and insertions of the compound tibialis posticus, and observes, " May 

 not the latter of the two muscles described above be regarded as a " tibialis posticus se- 



w 



cunclus vel internus ?" He also takes notice of the fact that in Cuvier*s * Myologie ' ^ the 

 last differentiated slip is lettered as tibialis posticus and its companion as flexor longus pos- 

 ticus. A second tibialis posticus obtains in Chlami/dophorus^, the two-toed Sloth ^, the 

 OrmtJiorhynchus ®, several other vertebrates, and occasionally, as an abnormality, in Man'. 



2. Inner Lumho-pelvic, Caudal^ and Belly-muscles, 



In an earlier section, antea p. 90, I have drawn attention to the small quadratus lum- 

 borum as being quite within the cavity of the chest, a trace of its tendons only emerging 

 beyond the diaphragmatic crura. Psoas muscles, again, are so aborted as to leave the 

 lumbar region meagrely clothed, indeed almost fleshless, a perfect contrast therefore 

 to what obtains in some of the Marsupialia, Camivora, and Eodentia. This one might 

 not be prepared to find ; for from the remarkable facility with which Tolypeutes curves 

 the body and again unrolls it, the supposition that the loin-muscles would take an active 

 share therein seems plausible. But, on the other hand, our animal and the Armadilloes 

 generally have but feeble saltatory power and habit^; and, as has been shown in the throe- 

 banded species at least, the great digastric muscle expanded within the carapace scorns to 

 supplant lumbar contractUe effort. But, looking to adaptation of parts, the absence of fleshy 

 masses within the loins serves well the economy of Tolypeutcs ; for greater spiwie results, 

 conducing to the neat packing of the abdominal viscera during the curvature of the body. 

 Psoas ligament.— I apply this term to a weU-marked and unusual ligament, in some 

 measure almost taking the place of psoas muscles. Somewhat like a backward con- 

 tinuation of the quadratus lumborum, or, indeed, rather simulating a rearward extension 

 of the crural tendons of the diaphragm, there is beneath and on each side of the bodies 

 of the posterior loin-vertebrse a stout tendon which proceeds towards the pelvic brim. 

 Anteriorly this springs from or is firmly fastened to a ventral carinal process of the second 

 lumbar vertebra, and therefrom, with a slightly outward divergent course, is continued 

 to and inserted on a small eminence answering to the anterior inferior spmous process of 

 the ilium in human anatomy. The psoas ligament is about 1^ inch long, narrow, flat, 

 and glistening, and at its pelvic termination partly covers and mingles with the super- 

 ficial facial structures of the sacro-iliac synchondrosis. It appears to have an important 

 bearing in spinal flexion, forasmuch as the hinge of movement at the loms turns on a pivot 

 at the intervertebral cartHage between the second and third lumbar vertebrae. Thus its 

 office may be compared to a guy-rope steadying and partiaUy regulating the curvilinear 

 tension of the pelvic parts to the spine in advance 



Hunterian 

 HjTtl's Monograpli 



L. c. p. 558. ' I*!- 260. 



Galton « On tte Myology of Cychthurus didactt/lus," Ann. & Mag. Nat. Hist 



424. and his memoir ' Orniihorhtfncl! jyarn^axi 



See Wood's Remark, Proc. Boy 



Witneas Prof. Owen's remarks on the movements of the Uvlng Armadillo. P. Z. S. 1S32, p. 135. 



