MR. J. C. GALTON ON DASYPUS SEXCINCTUS. ~>39 



the posterior rounded and smooth edge of the olecranon, overlap] >i ml: the insertion of the 

 epitrochleo-anconeus. 



4. Anconeus. — A very large, strong, fleshy muscle, of a triangular form, the apeN 

 uppermost. It arises from the whole of the extensive space (which may conveniently he 

 termed " olecranon fossa") hounded at the hase by the trochlea of the humerus, at tin- 

 sides by the strong ridges which run from the middle of the posterior a pect of Ihe bone 

 to either condyle. It is inserted into the smooth triangular surface which intervenes 

 between the posterior extremity of the olecranon and the humeral articular surface of the 

 ulna. Some fibres, however, are prolonged along the outer aspect of Ihe arm to blend 



with the origin of the extensor carpi ulnaris. 



The last-named element of the muscle is very well represented by Cuvier in one of his 



plates 1 . 



It has been already stated, in the description of the latissiun's dorsi, that the rforxo- 

 epitrochlear offset of this muscle is reinforced by some fibres which arise from the lower 

 part of the axillary costa of the scapula, near the inferior angle of this bone. Prof, 

 Rolleston has suggested to me that these fibres probably answer to an element of the 

 triceps figured in one of Cuvier's plates of the myology of the Badger ( Uraus melcs) as a 

 fifth extensor of the elbow 2 , and which is formed by a differentiation of the scapular 

 portion of the latter muscle into two fascicles, of which the most posterior is fixed at 

 the inferior angle of the scapula. On the other hand, fob fourth extensor, the dorw 



that, in Cuvier's figure, it arises from the latissimm dorsir—is but 



epitrochlien w , 



feeble in this animal. The following remark occurs in the letterpress appended to tin- 

 plates —"Le Blaireau est, comme on sait, un animal fouisseur, et la disposition dc c< 

 cinquieme extenseur doit augmenter considerablement la force d'extension de l'avant- 

 bras. Dans l'Ours, cette particular^ n'existe pas ; mais l'extenseur scapulaire est tres- 

 puissant et s'attache a presque tout le bord inferieur de l'omoplate" 3 . 



In the Otter (a swimmer) the portion of the triceps mentioned as ansing from the 

 angle of the scapula and passing to the elbow, in the Badger, is present ; but there seems 

 to be no true dorso-epitrochlear offset from the latissimus do™ present m tins ammal :. 



It has been further suggested to me by Professor Rolleston that the abovedesenbed 

 muscular element, which arises at the inferior angle of the scapula and terminates ; a the 

 olecranon, may be the serial homologue of a certain muse e which is present m the lower 

 limb of some animals (the « ilio-peroneair described by Mr. Mivart n> a paper upon the 



« Myology of Iguana «^ w f fj'stout lozenee-shaped muscle, arising from the inner 

 EpitrocMeo-anconens.-K fleshy ^JJJ ^ ori ins of t he pronator teres 



condyle of the humerus, ™°^^X^ to be in *^ d in *> the "*< 

 and JW carpi radialis, and passing o^^^ ion of the Mcep , 

 extremity of the olecranon, fusing also wit t J ^^ ^.^ ^ ^ 



This muscle is figured by Cut 



name of ancone interne 6 



100 



1 Op. cit pi. 259. fig. 2. , ^ dL pl m fig | _ 



3 Op. cit. pis. 81 and 82. , Qp ^ pl 260> 



6 Proc. Zool. Soc.Junel86/,p. **<>' 



4 



VOL. XXVI. 



