1896.] MYOLOGY OT? HOUBNTS. 1 75 



that muscle on the inner side of the opening, while the pouch 

 itself is deep to the whole of the pauniculus, in the latter the 



Kg- 9- 



-OPENING 



I- Pouch, 

 NSPHINCTER, f 



/ OF Pooch, 



'Sterno facialis. 

 PoHch-mnscles of Heteromys. 



pouch is formed by an evagiuation of the buccinator, to the fundus 

 of which a slip of platysma has beconie attached. 



Laiisshnus Dorsi. — This muscle has the same attachments that 

 it possesses in other Rodents ; the dorso-epitrochlearis is always 

 present, and reaches as far as the olecranon, though in Cricetomys 

 it is also inserted into the fascia of the forearm. 



Tmjjezv.ts. — In most of the Myomorpha as in the Sciuromorpha 

 there are three separate parts of the trapezius. The first of these, 

 described by Milne-Edwards ' and by Strauss-Diirckheim as the 

 clavo-cuciillaris, consists of the fibres passing between the occiput 

 aud the clavicle ; it is separated from the rest of the muscle by the 

 levator claviculae, and was found in the following animals : — 

 Myoxus, CHcetus, Cricetomys, Ilicroius, Ilyodes, Mus decumanus, 

 Hderomys, Bathyergus, aud Siphneus. In Oeorychus and Mus 

 harharus, however, this part of the muscle was not seen. The 

 second part, or acromio-cucullaris, consists of the fibres running 

 between the ligamentum uuchse and the anterior thoracic spines 

 on the one hand, and the acromial process and spine of the 

 scapula on the other ; it is usually separated from the third part 

 or dorso-cucullaris by a pad of fat. In all the animals dissected, 

 these two parts were separate with the exception of Cricetomys 

 and MyoxvLs. 



Rhomboidd. — The rhomboideus capitis is a distinct muscle, 

 while the major and minor are not separable one from another. 

 In Gricetus, Myoxus, Microtus, Oeorychus, Batliyergus, and 

 Heteror)\ys, part of the rhomboideus capitis rising from the outer 

 part of the occipital curved Kne is separated fi-om the rest and runs 

 to the inner half of the spine of the scapula, covering part of the 

 supra-si)inatus instead of going to the vertebral border. 



Serratus Magnus and Levator Anguli Scapulm. — The origins of 



' ' Etudes pour servii% &c.,' p. 04. 



