PROFESSOR WOOD ON THE NECK- AND SHOULDEE-MUSCLES. 
97 
has also, as I shall endeavour to prove, led to the concealment of the real homologies of 
the last-described muscle in the Rabbit, as well as of those of the muscle marked c in 
the figure, which has been confounded with it. The muscle which is called by Krause 
the basio-humeralis, presents, I believe, strong grounds for referring its homology to the 
cleido-mastoid of human anatomy. First, its lower attachment to the clavicle and its 
participation in the formation of the levator humeri is upon this supposition at once 
explained. Its deep position in relation to the muscles marked a and c, viz. the ster no- 
mastoid and cleido-occijpital , is also more in accordance with this supposition. Its origin 
from the basilar process takes place close to the suture between it and the mastoid bone, 
some of its fibres even arising from the latter. Its deep displacement may in fact be 
referred to the great development of the tympanic element necessary to support the 
enormous ears of the animal, at the expense of the occipital and mastoid development, 
which are small and compressed. A comparison of the relative position of the three 
muscles marked a, b, and c in the figures of the Rabbit, with those of the Hedgehog 
(Plate XI. fig. 22), and especially with those of its congeners, the Squirrel (Plate X. 
fig. 18), and the Norway Rat (fig. 19 and fig. 26, Plate XI.), will render the resemblance 
of the muscles herein treated as homologous, more plain than any description, and will 
tend to remove the confusion into which, by want of precision, the names of these mus- 
cles have been plunged. The relation of the muscle to the true levator claviculce (e) is 
thus one of juxtaposition merely, and not one of derivation. A further test of the accw 
racy of viewing this muscle as a cleido-mastoid is to be found in the arrangement of the 
group in the Ruminants as compared with the Solidungulata. 
In the fawn of a Fallow Deer dissected by my friend and former pupil Mr. Nettle- 
ship, from' whose sketch figure 20 (Plate XI.) was taken, it will be seen that the levator 
humeri ( b e ) ( ceplialo-humeral ) is made up of two parts (b and e) exactly corresponding to 
those of the Rabbit just described. They are marked with corresponding figures. The 
posterior or superior portion, or that corresponding to the acromio-tracheUen or levator 
claviculce ( e ), is the larger, and arises from the transverse process of the atlas. The 
anterior or inferior portion (b) joins the fibres of the rectus capitis anticus major («,), 
and is attached with it to the basilar process of the cranium. The two join about the 
middle of the neck to form one compound muscle ( b , e ), which passing over the shoulder 
without any clavicular “ inscription,” is inserted with the fibres of the pectoralis trans- 
versus (major) into the humerus just above the outer condyle. As the portion e corre- 
sponds clearly to the muscle which in the Rodents and Carnivora is attached to the 
metacromial process (and which Mivart and Murie found in the Hare and Rabbit to 
send some fibres down to the humerus), so the portion b is clearly the homologue of that 
which I have considered in the Rabbit as the cleido-mastoid , blending in the same way 
with the rectus capitis anticus major. To enhance the value of this proof, the sterno- 
mcistoid (maxillary) (a) in the fawn sends off a slip (a") to join, and thus to claim con- 
nexion with, its usual colleague, the cleido-mastoid , in its new connexions with the rectus 
capitis anticus major. 
mdccclxx. o 
