1890.] HELODERMA SUSPECTUM. 169 



(1) Its first head, and distinctly the largest, arises from the 

 entire posterior aspect of the shaft of the humerus, from the head 

 of the bone to the condyles. This part of the origin of the triceps 

 is comparatively carneous. 



(2) Another, and a very much smaller, carneous head springs 

 from a longitudinal line upon the posterior aspect of the shaft of the 

 humerus, extending from the tuberosity to a point a little above the 

 internal condyle. At the upper part of the shaft of the humerus 

 the insertional tendon of the latissimus dorsi passes between these 

 two heads. 



(3) A strong, cord-like tendon of the triceps springs from the 

 superior glenoid margin of the scapula, which merges into the fleshy 

 part of the muscle after it passes the head of the humerus. We find 

 given ofi" from the proximal end of this tendon, a thin, though 

 strong tendinous sheet, which passes across to the humeral head, 

 binding down as it does so the insertional extremity of the teres 

 minor. 



(4) Finally, we find a long flat tendon of the triceps arising from the 

 inner surface of the coracoid near its postero-inferior angle. This 

 crosses over to the upper part of the belly of the muscle, and merges 

 into it at a point immediately in front of the insertion of the lutis- 

 simus dorsi. A tendinous connection is made between this last- 

 named muscle and this coracoid-head of the triceps at the point we 

 have indicated. 



The triceps is inserted by a powerful tendon into the olecranon 

 process of the ulna, but no sesamoid develops therein as was found 

 to be the case in Parson's Chamaeleon by Mivart, and in Liolepis 

 belli by Sanders. This sesamoid is also alluded to by Hoff'mann as 

 the " patella ulnaris," in Bronn's ' Thier-Reichs ' (loc. cit. p. 632). 



Of the Musculature of the Antibrachium and Manus. 



36. Supinator longus. — This, one of the most important and con- 

 spicuous muscles of the forearm, arises semitendinous from the ex- 

 ternal condyle of the humerus, and immediately makes insertion 

 along the entire length of the shaft of the radius, upon its supero- 

 external aspect. Hoff'mann has very truly remarked in reference to 

 this muscle that " Man kann an diesem Muskel gewohnlich zwei 

 zuweilen drei oder selbst vier Portionen unterscheiden (letzteres bei 

 Iguana, nach Mivart). AUe diese Portionen entspringen von dem 

 Epicondylus s. Condylus exteruus humeri (bei Platydactylus auch 

 noch von dem unteren Drittel des Humerus, bei Liolepis oberhalb 

 des Condylus). Seine Insertion findet, wie gesagt, an der ganzeu 

 Lange des Radius statt." These remarks apply equally well to 

 the supinator in Heloderma. 



37. Extensor digitorum longus. — In this we have another muscle 

 which is prominently developed in the forearm of our present sub- 

 ject. Arising by a strong tendon from the external condyle it 

 passes down the limb to merge into a thin, flat tendon over the 

 wrist-joint, beyond which it trifurcates, a slip going to be inserted 



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