PHYSIOLOGICAL sERlKS. 



opposite mandible ; they check excessive divarication of the 

 mandibular rami. 2. Those concerned with the movement 

 of the palate the pterygo-sphenoidalis posterior and anterior 

 for the approximation of the posterior and anterior ends 

 respectively of the pterygoids, and a levator of the pterygoid 

 (pterygo-parietalis) . 3. A retractor of the voiuer (vomer 

 sphenoideus). 



D' Alton, Arch. f. Anat., 1834, p. 348; Duges, Ann. Sci. 

 Nat., t. xii. 1827, p. 337. 



C. 88. Head and neck of a Rook (Trypanocoraai frugilegus}^ in 

 which the tongue and pharynx have been displaced to show 

 the muscles of the jaws and hyoid. They are few and 

 simple. The jaw is depressed by a single-bellied muscle, 

 very similar in its position and general appearance to the 

 depressor of Ornithorhynchus shown in No. ('. 9."). It is 

 possibly homologous to the posterior belly of the mammalian 

 depressor. The beak is closed by a double temporalis and 

 a well-developed pterygoid. The geniohyoid is the most 

 important muscle connected with the hyoid apparatus, it 

 passes backwards from the lower jaw and is wound round 

 the apex of the hyoid cornu it protrudes the tongue. 

 Retraction is caused by the styloglossus. 0. C. (34 Y n. 

 Shufeldt, Myology of the Raven, London, 1890, p. 15. 



Presented by St. George Mivart, Esq. 



C. 89. Head and anterior part of the sternum of a Cape Hyrax 

 (Procavia \_IIy ra.u] capensis), showing certain muscles of 

 the neck. From the upper ascending ramus of the jaw on 

 either side there arises a voluminous muscle, whose fibres 

 pass downwards and backwards some of them are inserted 

 upon the mantibrium sterni, but the majority meet those of 

 the corresponding muscle of the opposite side in a median 

 raphe. The function and houiologies of this muscle are 

 obscure, but it possibly represents a migrated portion 

 (sterno-maxillary) of the sterno-mastoid, such as occurs in 

 the Horse and other Ungulates. Its presence gives the 

 well-known puffy appearance to the neck of the Hyrax. 

 0.0. 64z<. 



George, Ann. Sci. Nat., ser. 6, t. i. 1874, p. 102. 



