94 
PROFESSOR WOOD ON THE NECK- AND SHOULDER-MUSCLES. 
The splenius is hereby transformed from a spinal muscle into one acting upon the com- 
bined fore legs and head, moving freely over the spine, and it becomes a notable accessory 
force in aid of the action of digging and burrowing with the snout and fore paws. 
The muscle just described seems to correspond to that described by Meckel as a very 
strong rhomboid, attached to the moveable ossicle. The muscle upon which it rests, how- 
ever, seems to me to be clearly the complexus, witli the large trachelo-mastoid muscle to its 
outer side, constituting the only muscular layer which intervenes between the muscle in 
question and the semispinalis and multifidus system of fibres, with the obliqui and recti of 
the occiput. The direction of the fibres of this muscular layer corresponds with that of the 
complexus, viz. from the transverse processes forwards and a little inwards to the median line 
of the occiput, where the two fellow muscles are closely placed together at their insertion. 
Levator claviculce Muscle. — Synonyms : The “ levator scapulae major vel anterior ” of 
Douglass and Burmeister ; the “ omo-' or “ acromio-trachelien ” of Cuvier and Meckel; 
the acromio-basilar of Vjcq d’Azyr ; the cla vi o-traclcelien of Church ; the basio-liumeralis 
of Krause ; the Kopf-Arm-Muskel of Peyer ; the transverso-scapulaire of Strauss-Durck- 
heim; the omo-atlanticus of Haugiiton ; and the cervico-humeral of Humphry. 
The homologies of this muscle in the Mammalia form too extensive a subject, and one 
presenting too many complex modifications, to be fully entered into in this paper. I will 
content myself with indicating the principal changes which occur in it, selecting such 
specimens as may throw light upon the developments I have found in the human subject. 
In by far the greater majority of animals the muscle arises from the transverse process 
of the atlas singly. In some it extends also to that of the axis ; and it seems to represent 
that which in Man and the higher Simiadce are the two upper digitations of the levator 
anguli scapulae. In the Rodents and Pachyderms, however, we shall find that, by 
becoming amalgamated by longitudinal and lateral fusion with the recti capitis, it may 
be attached to the lateral or basilar processes of the occipital bone. 
In the Gorilla, Chimpanzee, and Orang it is always present, arising from one or two 
of the upper cervical transverse processes, and inserted into the clavicle external to its 
centre. This insertion into the clavicle, which is found, as we have seen, in the human 
subject, and has given to it the name of levator claviculce, becomes in the lower Qua- 
drumana, by external transposition, shifted to the upper border of the acromion process 
of the scapula (omo- or acromio-trachelien). Its clavicular attachment, however, reap- 
pears, according to Mivart and Murie, in the Nycticebus tardigradus or Slow Loris 
(Proc. Zool. Soc. 1865, p. 243), and is found universally in the Bats, attached to the 
outer end of the clavicle close up to the insertion of the trapezius. In the former animal, 
as described by the above authors, the muscle arises singly from the transverse process 
of the atlas, the levator anguli scapulae arising as far forwards as that of the axis, as well 
as from all the cervical transverse process behind that point. The single origin prevails 
also in most of the lower Quadrumana. In the Papio Mormon and Magot it arises from 
the axis as well as the atlas (Cuvier and Laurillard, plates 29 & 30). In these Apes, 
and in Ateles and Callithrix also, its scapular insertion is covered by the front fibres of 
