332 MESSRS. MURIE AND MIVART ON THE [Apr. 11, 
The connexion of this second part of the sterno-cleido-mastoid 
with the mandible offers an interesting resemblance to the attach- 
ment of the same muscle in the Horse. 
Meckel describes this muscle, in the Hyraz, as connected with the 
mastoid process by a strong and long tendon *. 
In the Guinea-pig this portion of the muscle did not arise from the 
jaw, but from the skull, as usual. 
The third part of the sterno-cleido-mastoid is very slender, and 
not unlike an omo-hyoid in appearance (see fig. 3, S.c.m.3). It 
arises from the paramastoid, and joins deeply the conjoined portions 
of the two foregoing parts of this muscle. 
This may be what Meckel alludes to in the passage just referred 
to, and appears also to be the “ troisiéme ventre” spoken of by him, 
at page 162, as being often found in Man. 
Fig. 3. 
Diagrammatic view of superficial muscles of the neck. 
P.m. Platysma myoides, its attachments to the lower jaw and forearm; above, 
it is cut open and drawn back by hooks to expose S.c.m.3, the third small 
portion of the sterno-cleido-mastoid. C.#. Cephalo-humeral. S.se. Sterno- 
scapular. 
The longus colli has attachment upon the ventral surface of the 
cervical vertebree, the 2nd to 7th inclusive, and is inserted in the 
thorax, on the bodies of the first six dorsal vertebree. 
The rectus capitis anticus major arises from the cervical verte- 
bree, from the 6th to the 3rd, and is inserted into the basioccipital. 
We found no trace of the rectus capitis anticus minor, at least as 
a separate muscle. 
The rectus lateralis is well developed, arising from the transverse 
process of the atlas, chiefly its anterior surface, and being inserted 
into the paramastoid. 
* Anat. Comp. tome vi. p. 163. 
