98 



Basic Structure of Vertebrates 



called "visceral," but a better name is "branchiomeric," which 

 implies only that such segmentation as the muscles exhibit corresponds 

 to that of the branchial structures. 



In reptiles, birds, and mammals, muscles which in embryonic 

 origin and in innervation correspond to these branchiomeric muscles 

 of fishes can be recognized in the muscles of the jaws and floor of 

 mouth, small muscles of the larynx and pharynx, and two still 

 smaller ones (stapedius and tensor tympani) related to the 

 auditory mechanism of the mammalian eardrum, and in a complex 

 set of thin superficial facial muscles which effect small movements 



M. ORBICULARIS OCULI 



NASAL 

 ZYGOMATIC' 

 AURICULO-LABIAL SUP. 

 AURICULO-LABIAL INF. 



TRIANGULAR 



A. ATELES 



M. ORBICULARIS OCULI 

 NASAL 



M.QUADRATUS LAB 1 1 SUP 

 CANINE- 



M. ORBICULARIS OR I 



M. RISORIUS 



M. QUADRATUS LAB II INF 



M. MENTAL IS 



^ZYGOMATIC 

 ^.--^~*M. PLATYSMA 



B HOMO. 



TRIANGULAR 



Fig. 96. Mimetic muscles in monkey (A teles) and man. (A) Ateles (redrawn from 

 Wilder after Ruge). (B) Homo. The similarity of these muscles both in function 

 and in relations attests their similar genetic derivation. (Courtesy, Neal and Rand: 

 "Chordate Anatomy," Philadelphia, The Blakiston Company.) 



