1896. | MYOLOGY OF RODENTS. 175 
that muscle on the inner side of the opening, while the pouch 
itself is deep to the whole of the panniculus, in the latter the 
Fig. 9. 
~~OPENING 
SLATS, ao : et *}Poucu . 
ye \SPHINCTER 
# oA oF Poucn, 
‘STERNO FACIALIS . 
Pouch-mnuscles of Fleteromys. 
pouch is formed by an evagination of the buccinator, to the fundus 
of which a slip of platysma has become attached. 
Latissimus Dorsi.—Vhis muscle has the same attachments that 
it possesses in other Rodents ; the dorso-epitrochlearis is always 
present, und reaches as far as the olecranon, though in Cricetomys 
it is also inserted into the fascia of the forearm. 
Trapezivs.—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 
clayo-cucullaris, consists of the fibres passing between the occiput 
and the clavicle ; it is separated from the rest of the muscle by the 
levator clavicule, and was found in the following animals :— 
Myoxus, Cricetus, Cricetomys, Microtus, Myodes, Mus decumanus, 
Heteromys, Bathyergus, and Siphneus. In Georychus and Mus 
barbarus, however, this part of the muscle was not seen. The 
second part, or acromio-cucullaris, consists of the fibres running 
between the ligamentum nuche 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 Myowus. 
Lhomboider.—The rhomboideus capitis is a distinct muscle, 
while the major and minor are not separable one from another. 
In Cricetus, Myoxus, Microtus, Georychus, Bathyergus, and 
Heteromys, part of the rhomboideus capitis rising from the outer 
part of the occipital curved line is separated from the rest and runs 
to the inner half of the spine of the scapula, covering part of the 
supra-spinatus instead of going to the vertebral border. 
Serratus Magnus and Levator Anguli Scapule.—The origins of 
1 « Btudes pour servir, &c.,’ p. U4. 
