THE EXTREMITIES OF ORYCTEROPUS CAPEXSIS. 5G9 



cervical region, immediately after parsing beyond the inferior extremity of tin' vertical 

 ramus ol* the mandible, they spread out, and soon give off from the outer side a 1> inch 

 of fibres, which curve gradually outwards and downwards, and, passing over the deeper 

 layer of the paihticu//'.* conto§u$, are lost in the dense (ibro-adipos. subcutaneous tissue 

 of the neck. 



Immediately underneath the muscle, dining the whole extent of its passage along the 

 neck, lies the enormously developed gtthmaxilhufy gland, the strong fibrous capsule of 



the latter only intervening. 



On reaching the anterior border of the chest, the 



but 



increases in thickness, and, passis over the insertion of the .s/ernowxtoid and manu- 

 brial portion of the pectoralis major t is inserted into the middle line of the sternum, 

 from immediately below the insertion of the former muscle to about the beginning ol 

 the posterior or inferior third of the bone, its fibres meeting those of its fellow in the 

 middle line, but not decussating with them. 



A few fibres seem to be prolonged into the fascia covering the abdomen; and a few 

 others are given oil' from the outer edge of Ihe muscle, on a level with its lowest point of 



insertion, to be lost over the ascending fibres of the dcrmo-hu merien. 



Since this muscle coexists with an upward extension of the reel v abdominis, and 

 with a downward prolongation of the ster u <>-,,) a atold, the only alternative left is to regard 

 it, with Halbertsma, as a muscle sui generis, or to agree with Professor Turner 1 in con- 

 sidering it a differentiated portion of the pannicul ? eartwsus — a conclusion in which I 



am inclined to concur. 



Prof. Humphry, though he has given a full description and a good representation (loc. 

 cit. pi. 13) of the panniculus camosus 2 , has not considered the factor just described in 

 the lio-ht of its bearings upon the question of the nature and affinities of the musculus 



sterna I is. 



Cuvier, in his plates of the Orycteropus*, gives a good representation of this muscL 



under the name of " thoraco-facien." It is figured on the inner of two divisions of th< 



platysma, the outer of which passes over to the external aspect of the arm and forearm 



and is termed by him " dcrmo-humerien 



Platysma my aides. — Tin's element of the panniculus camosus is very well developed, 

 and consists of a strong and somewhat coarse muscle, which arises from the whole extent 



>> 



-^ 



of the inferior edge of the jugal arch and, seemingly, in part from the body of the malar 

 bone, passes downwards and outwards over the shoulder, and along the outer aspect of 

 the arm, to be inserted, along the radial edge of the forearm, in the fascia which clothes 

 its external aspect. At the middle of its course it is crossed by a band of muscular 

 fibres, which curve outwards and downwards from the outer edge of the musculus iter* 

 nails to be finallv lost in the subcutaneous tissue of the neck. 



1 " On the Musculus Sternalis," Journ. of Anat. ft Phys., Cambridge, 1 867, 1st ser. vol. i. p. 248. To the animal 

 cited by Prof. Turner in support of his views, at p. 253 in the above paper, I am able to add from my own observa- 

 tions Hptrisb (cristata?). The muscle in qur-tion fa well repn sited by Cuvier, under the name of "thoraco- 

 facien," in his figures of this animal, op. cit. pi. 228- 



292 



3 



Op 



4 



