250 



HISTORY OF THE HUMAN BODY 



encasing- the trunk in a sub-cutaneous muscular sheet. This 

 is the panniculus carnosus, and is primarily employed in mov- 

 ing and wrinkling the skin as a defense against insects. In 

 the monotremes the portion derived from the pectoralis ex- 

 tends over the entire ventral aspect of the body, and where 

 it meets the marsupial pouch and the cloacal orifice forms 



D 



FIG. 67. Phylogenesis of the panniculus carnosus. [After TOBLER.] 



(A) Macropus bennett (kangaroo). (B) Cynocephalus hacmadryas. (C) Cerco- 

 pithecus sabaeus. (D) Cercopithecus cephus. 



from its fibers certain more specialized slips to serve as 

 sphincters (sphincter marsupii and sphincter cloacce). 



A panniculus carnosus, perhaps here mainly a contribution 

 from the latissimus, is also present in marsupials (Fig. 67, A) 

 and covers the flanks with fibers that converge to an insertion 

 into the humerus. From these it is directly continued to the 

 Insectivora and Carnivora, and to other Orders of mammals. 

 Its action is seen in the shaking of the skin of a wet dog or 

 the twitching along the outer portion of the legs of horses 

 and cattle when these surfaces are stimulated by the bite of 

 an insect. In the lower primates, the panniculus appears as 



