REPTILIA. 



279 



in the turtles appears to have no scapular 

 origin. 



Fig. 197. 



Myology of the Tortoise 



71, pronator teres (insertion of) ; 72, pronator 

 quadratus ; 75, radialis internus ; 88, flexores digi- 

 torum breves ; 90, interossei digitorum manus in- 

 terni. 



There is only one supinator*, which is in- 

 serted into the wrist; it arises from the ex- 

 ternal condyle, but in the turtles this muscle 

 is wanting. Both the pronators of the fore- 

 arm are present in the land-tortoise ; however, 

 the pronator quadratus is very small, and 

 situated close to the carpus. 



Muscles of the Hand. The muscles of the 



Fig. 198. 



Myology of the Tortoise. 



86, abductor digiti tertii, quarti et quinti;. 90, 

 interossei digitorum manus interni. 



fingers are, in the turtle, few in number, their 

 hand being so flattened out into the shape of 

 a fin or oar as to require neither flexors nor 

 extensors of the fingers; in these, therefore, 

 the analogue of the extensor digitorum coin- 

 munis is confounded with the general apo- 

 neurosis. The flexor communis is slightly 

 more distinct ; and the interossei, the abduc- 

 tors and adductors of the thumb and of the 

 fifth finger exist, the latter serving to expand 

 or to contract the oar. 



* Bojanus regards the muscle marked 79 (Jig. 192) 

 as a supinator brevis. 



In spite of the extreme shortness of the 

 hand in the land-tortoises, the muscles are 

 well developed, and the extensor communis, 

 the extensor, and the long abductor of the 

 thumb, the flexor sublimis, the flexor pro- 

 fundus, the adductor of the thumb, and the 

 abductors of the little finger, as well as the 

 interossei, are met with. 



Muscles of the Pelvis. In the tortoise the 



Fig. 199. 



Myology of the Tortoise. 



a, glans penis ; b, bulbus penis ; c, vein derived 

 from ditto; 50, flexor caudae lumbalis; 51, flexor 

 caudae obturatorius ; 52, flexor caudse ischiadicus; 

 55, protrahens penis. 



muscle analogous to the quadratus lumborum 

 spreads out beneath the carapax between 

 the antepenultimate ribs: it is inserted into 

 the ileum near the articulation of that bone 

 with the sacrum, that articulation being in 

 the Chelonians moveable. 



This mobility of the pelvis is aided by the 

 analogue of the rectus abdominis, which, 

 instead of spreading out beneath the belly, is 

 attached under the posterior extremity of the 

 plastron by two fleshy bellies, one in front 

 and the other behind ; both run to be inserted 

 into the anterior margin of the external ramus 

 of the pubis, 



Muscles of the Thigh. In the land and 

 fresh-water tortoises, although the ossa ilii 

 are very narrow, the mu>scles belonging to 

 the thigh are of considerable thickness. The 

 glutaeus maximus, which might almost be 

 mistaken for a pyramidalis, is only attached 

 to the ileum by a small proportion of its 

 fibres, the remainder are derived from the 

 transverse apophyses of the caudal vertebrae. 

 The glutaeus medius and minimus, united 

 together at their origin, constitute a mass 

 which arises from all the external surface of 

 the ileum, from its anterior border, slightly 

 from its internal surface, and even from the 

 inferior surface of the seventh rib : this muscle 

 divides into two tendons, one of which, that 

 of the glutasus medius, is inserted into the 

 trochanter ; the other, that of the glutaeus 

 minimus, a little lower down into the body o. 

 the femur. 



The obturator internus is a very strong 

 muscle arising from the upper aspect of the 

 internal ramus of the pubis, and winding 

 around the ischium, as in mammalia, to be 

 inserted into the great trochanter, 



The quadratus femoris exists, but neither 

 gemelli nor pyramidalis are present. 



There is no psoas ; but the iliacus is strong, 

 and arises from the upper part of the internal 



T 4 



