ADAMS, PHYLOGENY OF THE JAW MUSCLES 91 



The jaw muscles of Sphenodon are slightly more subdivided than those 

 of Chelydra, in correlation with the more open construction of the skull. 



MUSCLE 8 OF THE ADDUCTOR OR TEMPORAL GROUP 

 (INNERVATED BY V 3 ) 



Capiti-mandibularis. 



(a) Capiti-mandibularis superficialis (C. m. s.). 



= Outer fibers of Osawa's temporal. 



(b) Capiti-mandibularis medius (C. m. m.). 



= Temporalis, Osawa (superficialis). 



(c) Capiti-mandibularis profundus (C. m. p.). 



= Pterygoideus externus, Osawa. 

 Pterygoideus anterior (Pt. a.). 



MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP 

 (INNERVATED BY VII) 



Depressor mandibular (D. m.). 



= Parieto-mandibularis, Osawa. 



MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP 

 (INNERVATED BY V z ) 



Capiti-mandibularis. — This muscle is the large muscle mass of the rep- 

 tiles and it is taken to represent the mother mass of several muscles, as is 

 mentioned elsewhere in this paper. It seems to be the conjoined masseter 

 and temporal fibers, so that the divisions of the muscle are given the 

 names used below. 



(a) Capiti-mandibularis superficialis (C. m. s.). — This part of the 

 temporal mass consists of the fibers that always extend over the deeper 

 fibers in the reptiles. 



(b) Capiti-mandibularis medius (C. m. m.). — This is the inner part 

 of the main mass, or the temporal of Osawa. The capiti-mandibularis 

 mass arises in the temporal fossa on 'the parietal, squamosal, quadrate, 

 the inner side of the jugal and from the temporal fascia. It is inserted 

 on the point of the coronoid and on the inside and outside of the posterior 

 third of the mandible. 



(c) Capiti-mandibularis profundus (C. m. p.). — This deeper section 

 of the temporal mass is separated in this form from the rest of the tem- 

 poral mass. It arises on the parietal, postfrontal, prootic, epipterygoid, 

 the membrane between epipterygoid and the prootic and from the outer 

 face of the pterygoid. 



