78 MR. A. SANDERS ON THE [Jan. 6, 



fenestra, and is inserted into the ventral surface of the humerus 

 for about half its length, commencing at the head. 



Triceps (figs. 1 & 3, Tr. e.) in this species has four origins. The 

 outer head arises from the external surface of the humerus for nearly 

 its whole length, commencing immediately within the insertion of 

 the infraspinatus. 



The long head (figs. 2 & 3, Tr. I.) arises from the posterior 

 border of the scapula just above the glenoid cavity, and gives a 

 tendon which passes across the teres minor in the usual manner to 

 be inserted into the humerus close behind the anterior level of the 

 insertion of the infraspinatus. 



The inner head (fig. 2, Tr. i.) is divided into two distinct por- 

 tions : one part arises by muscular fibres from nearly the whole 

 length of the inner surface of the humerus ; at about the junction of 

 the distal with the middle third it joins the other portion, which 

 arises by a narrow tendon from a ligamentous band, which goes from 

 the external angle of the sternum to the inner surface of the scapula, 

 dorsad of its point of junction with the coracoid ; at the point of 

 insertion the tendon spreads out into a broad expansion, one end of 

 which is attached to the above-mentioned ligament, while the other 

 end is connected to the posterior angle of the coracoid close to the 

 origin of the coraco-brachialis longus. All four heads join together, 

 and developing a sesamoid bone in the substance of their common 

 tendon are inserted into the proximal end of the ulna. The ar- 

 rangement of this muscle in this species is just opposite to that 

 found in P.japonicum, in which lizard the outer head, and not the 

 inner head, is the one which is divided into two parts*. 



Extensor carpi ulnaris (fig. 3, E. C. U.) arises by two heads — one by 

 a flat tendon from the outer condyle of the humerus, the other fleshy 

 from the proximal end of the ulna ; it is inserted by a narrow tendon 

 into the base of the metacarpal bone of the fifth digit. 



Supinator longus (figs. 1 & 3, S.L.) arises from the external 

 condyle of the humerus, and is inserted into the whole length of the 

 radius. 



Extensor longus digitorum (fig. 3, E.L.) arises from the outer 

 condyle close to the last; half of it goes to join that muscle at about 

 the distal third of the radius ; the remainder develops three short 

 tendons, which are inserted into the base of the 2nd, 3rd, and 4th 

 metacarpal bones ; the tendon for the fourth digit is given off higher 

 up than the other two. 



Extensor ossis metacarpi pollicis (fig. 3, E.M.) seems very con- 

 stant ; in this species it is a triangular muscle precisely resembling 

 that of L. belli. 



Extensor brevis digitorum (fig. 3, E.B.) consists of five short 

 muscular slips which arise from the dorsal surface of the carpus ; 

 each of these slips ends in a tendon which is inserted into the ter- 

 minal phalanx of its respective digit. 



There are two muscles which have the attachment of pronators of 

 the forearm. The first may be called 



* Loo. cif. p. 416. 



