100 
PROFESSOR WOOD ON THE NECK- AND SHOULDER-MUSCLES. 
and Laurillakd. In the Mole (Plate X. fig. 11, c) a broad and large muscle, parallel 
with the sterno-mastoid (a), seems to embody in itself both the clei do-occipital and cleido- 
mastoid ; in this animal the origins of the sterno-mastoids cross each other over the 
median line. In the Bats, which have no cleido-mastoids, the cleido-occipital muscle 
seems to be represented by the occipital or neck portion of the long extensor of the 
wings, called by Cuvier the “ dorso-occipital ,” which passes superficially over the clavicle 
to the thoracic limb, and is, apparently, the homologue of the cephalo-humeral. In the 
Armadillo Mr. Galton describes, under the name of the levator clavicular, a muscle arising 
from the occipital aponeurosis outside the trapezius ; it is placed along the edge of, and 
parallel to, the cleido-mastoid, and is inserted close to its outer side into the clavicle. 
It is figured also by Cuvier and Laurillard in the same animal. It is clearly the homo- 
logue of the cleido-occipital, and not of the levator clavicular . In the Great Anteater 
the muscle is very large and distinct, excluding the trapezius altogether from the occiput : 
it was considered by Meckel as a second cleido-mastoid in this animal. 
Through the claviculate and semiclaviculate Kodents the homologies of the cleido- 
occipital muscle can be clearly traced to the upper or cephalic element of the compound 
cephalo-liumeral muscle which forms so important a part in the shoulder of the Carni- 
vora. In the common Squirrel (Plate X. fig. 18, c ) the muscle is connected at the occi- 
put with the cranial attachment of the trapezius (T), which overlaps it superficially; 
below it is attached to the clavicle superficial to the cleido-mastoid {b). Intervening 
between it and the scapular attachment of the trapezius emerges the acromio-trachelien 
( e ), to be attached to the acromial process superficial to the last-named muscle. This 
intervention of the acromio-trachelien, which I have before especially noted in this paper, 
is important as enabling us to discriminate between that portion of muscle which I take 
to form the homologue of the cleido-occipital, but which in the Carnivora and some 
Kodents is described by preceding writers as the clavicular portion of the trapezius itself. 
In the Flying Squirrel, the Beaver, and the Surmulot, this part forms equally a separate 
and distinct muscle, attached to the occiput near the trapezius, and separately to the 
clavicle below (see Plate XI. fig. 26, c). In the latter, as seen in the figure (c), the lower 
end is shifted outwards towards the acromial end of the clavicle, and with it is shifted 
the origin of the cleido-mastoid ( b ), so as still to preserve its relative superficial position ; 
it is as if the clavicle had been elongated mainly at the inner or sternal end. In these 
animals the muscle has been described by anatomists as a second cleido-mastoid, but its 
invariable occipital attachment, the direction of its fibres, and its wide separation at its 
upper attachment from the real cleido-mastoid sufficiently distinguish it from that muscle. 
In the Marmot it is very large, and excludes the trapezius both from the occiput and 
the clavicle; anteriorly it passes forward superficial to the cleido-mastoid, and joins the 
hinder edge of the sterno-mastoid. In the Capybara and some other Kodents also, and 
in the Carnivora generally, it excludes the trapezius from the occiput, and is inserted 
into the movable clavicle, or the aponeurotic “ inscription ” which represents it, to which 
it is attached superficial to the cleido-mastoid, forming with it the cervical or cephalic 
