MUSCLES OF THE HEAD. 



61 



Fis-. .06. 



arm of the squamosal, and from the j)osterior and inferior border 

 of the eartilag-inous tympanic ring-. The two parts unite and are 

 inserted into the hinder angle of the lower jaw. Cuvier correctly 

 considers that only the anterior portion corresponds to the digastri- 

 cus, the posterior answering- to the m. cervico-viaxiUaris of snakes. 

 It draws the lower jaw down and opens the mouth. 



14. M. temporalis (Figs. 49, 52, ^6, 57 f). 



Cuvier, m. iemporaUs, I, I.e., p. 138. — Dugès, sous-rupéo-temporo-coronoidieii. 



This muscle, tog-ether with the m. pteryrjouleus, occupies the space 

 between the prootic and the eyeball ; it arises by the greater 

 part of its fibres from the 

 upper surface of the pro- 

 otic ; it passes, narrowdng-, 

 beneath the anterior arm of 

 the squamosal, then over 

 the pterygoid bone, between 

 this and the maxillary and 

 quadrato-jugal, receiving- on 

 the way other fibres which 

 arise from the anterior border 

 of the inferior arm of the 

 squamosal and from the 

 anterior circumference of the 

 tympanic ring. The collected 

 fibres end in a broad, flat 

 tendon, which is inserted into 

 the inner surface of the so- 

 called proc. coTono'idevs. 



iluscles of the lower jaw of Rana esculenta. 



d >r. deltoideus. 



<l>n M. depressor maxillae, its origin where covering 



the m. temporalis reflected at *. 

 Id M. latissimiis dorsi. 

 m M. masseter. 

 ■t M. temporalis, origin. 

 /' Lower portion of same. 



15. M. pterygoideus (Figs. 497:1, 52, ST pf)- 



Cuvier, m. temporalis, II, I.e. — Zenker, on. massefericn-t, I.e., p. 25. — 

 Dugès, pré-riipéo-pterygo-maxillaire, 31. 



This is partly covered by the foreg-oing-, and lies between it and 

 the eyeball. It arises at the inner wall of the orbit from the 

 frontoparietal, and from that portion of the prootic Avhieh may be 

 regarded as the ala magna, above the m. retractor JjidJA. The muscle 

 is broad, and compressed from before backwards : it runs down- 

 wards covered by the vi. temporalis, and soon passes into a long, 

 thin tendon (Fig-. 57/;/), which is inserted, behind the m. temporalis 

 and immediately in front of the joint, into the inner surface of the 

 lower jaw. 



