86 ANNALS NEW YORK ACADEMY OF SCIENCES 



MUSCLES OF THE ADDUCTOR OR TEMPORAL GROUP 

 (INNERVATED BY V 3 ) 



Capiti-mandibularis superficialis (C. m. s.). — This muscle covers the 

 lower part of the temporal muscles. Its fibers extend posteriorly as they 

 do in most urodeles. It arises on the whole outer face of the squamosal 

 and extends over the pterygoid bone to be inserted on the posterior half 

 of the exterior face of the mandible. 



Capiti-mandibularis profundus (Cm. p.). — This is the posterior slip 

 of the muscle called "temporal" by Osawa. It is a thin muscle that arises 

 on the third neck vertebra, extends forward to join the pterygoideus 

 anterior and is inserted on the inner side of the mandible. 



Pterygoideus posterior. — Very small in this form. 



Pterygoideus anterior (Pt. a.). — This is the anterior part of the tempo- 

 ral muscle of Osawa. It arises on the pre-frontal and fronto-parietal, 

 extends under the eye and converges rapidly to a narrow tendon, and is 

 inserted on the coronoid process and in the fossa. This muscle is a part 

 of the muscle usually called a temporal muscle, but it is considered as the 

 homologue of the muscle found in the reptiles called pterygoideus anterior 

 in this paper. 



MUSCLES OF THE DEPRESSOR OR DIGASTRIC GROUP 

 (INNERVATED BY VII) 



Depressor mandibulce (D. m. 1 , D. m. 2 ). — This is a double-headed mus- 

 cle, as it is in all of the amphibians. It arises on the dorsal and posterior 

 part of the squamosal, with a second part arising from the dorsal fascia. 

 The anterior part arises from the otic region and from the posterior, 

 upper face of the squamosal. Both parts are inserted on the upper and 

 outer face of the angular bone of the mandible. 



AMPIIIUMA 

 Plate V, Fig. 5 



The skull is elongated and there is a prominent sagittal crest so that 

 a deep fossa is formed for the muscles of the upper part of the skull. 

 The skull roof is open so that the muscles have free play, as in most 

 urodeles. The pulley arrangement of the dorsal muscles gives a very 

 definite action to the jaws and is probably correlated with the backward 

 extension of the capiti-mandibularis profundus, which is attached to the 

 vertebra? of the neck. 



