168 MR. F. G. PARSONS ON THE [Jan. 14, 
Deltoid.—This muscle in the Myomorpha has the usual three 
parts, but the intervals between them are hardly noticeable ; more- 
over, they are all inserted into the humerus at the same point. The 
portion rising from the spine of the scapula, instead of being the 
smallest, as in the Hystricomorpha, is usually the largest. This 
description applies to all the animals examined, with the exception 
that in Bathyergus, Georychus, and Siphneus the intervals are so 
ill-marked that the muscle appears single as in Man. 
Supraspinatus, Infraspinatus, and Subscapularis.—These resemble 
the same muscles in the other Rodents in having the human attach- 
ments. In some, e. g. Cricetomys, the supraspinatus is larger than 
the infraspinatus ; but, as a rule, the reverse is the case. Milne- 
Edwards points out that in Siphneus the supraspinatus only occupies 
the anterior three-fourths of the fossa, the posterior part giving 
attachment to the rhomboid. 
Teres Major.—This has the usual attachments, its relation to the 
tendon of the latissimus dorsi is variable, and depends on the extent 
to which that muscle is wrapped round the lower border of it. In 
Myouus, Cricetus, Rhizomys, Microtus, Mus barbarus, and M. ratius 
the teres major is wrapped round by the Jatissimus dorsi, so that 
the latter is inserted anteriorly to it. In Cricetomys, Georychus, 
and Bathyergus the wrapping round is not so complete, and the 
teres major is inserted in front of the latissimus dorsi. In Siph- 
neus the arrangement seems to be the same. 
Teres Minor.—This muscle closely agrees with the description 
given of it in the other Rodents. It is very rarely a distinct 
muscle, Cricetomys being the only animal in which it could be 
described as well-marked. It is interesting to notice that a strong 
, 
P_-DEL, 
a 
INFRA.SPIN. | 17 
T.MAJOR! 
TRICEPS- 
Shoulder-muscles of Rhizomys. 
