328 SHOULDER-GIRDLE IN MONOTREMES, 



CuviER and Laurillard, in PI. 265, figure the trapezius as (a) 

 trapeze ou cucullaire, portion occipitale ; (a^) idem, portion cervi- 

 crtl(! ; (cr) idem, portion dorsale ; and they call the whole " dorso- 

 sous-acromien." 



M. latissimus dorsi et M. uorso-epitrochlearis. 



Echidna : Anterior, podtrior, and scapular portions ; the latter = M. 

 dor.io-epitrochleariti, Mivart. Scapidar and anterior portions ; posterior por- 

 tion = M. dorso-antibrachialis, Westling, Leche. 



OHN'iTHORHYNCHOrf : Superficial and deep portions, Owen ; Latissimus 

 d.orsi, one muscle only, and a dorso-epitrochlearis, Coues ; one muscle onlyt 

 ileckel. 



ECHIDN'A. 



The latissimus dorsi is differentiated into three portions : — 

 anterior and posterior dorsal, and scaj)ular. 



Origin, {a) Posterior dorsal portion. — This muscle arises 

 by fleshy bundles from the 8th to the 14th rib inclusive. The 

 fasciculi from all the^^e ribs are well developed, except from the 

 14th rib, which has but a few fibres arising from it. No fibres 

 arise from the last rib, the 15th. (Fig. 11, Lt. D.I'.) 



Insertion. The digitations run forwards and outwards and 

 coalesce to form a broad sheet of muscle, which becomes narrower 

 as it approaches the olecranon, and also becomes cleft into two 

 layers. One of these, the superficial and larger division, repre- 

 senting the M. dorso-epitrochlearis, runs downward and is attached 

 by tendon to the sheath of the M. flexor carpi ulnaris, which is 

 inserted on the pisiform bone. The deeper and smaller layer is 

 inserted on the ventral face of the inner portion of the internal 

 condyle ; being placed superficial to the insertion of the anterior 

 division of the latissimus now to be described. 



Origin, (h) Anterior dorsal portion. — This part of the 

 latissimus arises from the Ist-lOth or 11th spine of the dorsal 

 vertebne. The origin from the lst-3rdis by fleshy bundles, and 

 by the dorso-lumbar aponeui'osis fiom the rest. 



Insertion. The muscle runs outwards and a broad sheet 

 of muscle is developed. As the muscle approaches the internal 



