1901.] 



ME MUSCLES OE THE UNGULATA. 



669 



Ungulates except Hyrax (see text-fig. 88) ' ; it rises from the 

 paramastoid and outer side of the base of the paroceipital pro- 

 cesses, and is inserted into the posterior projection at the upper 

 end of the stylo-hyal bone. In the Horse (56, 57) the muscle 

 covers the outer side of the eustachian air-pouch. 



In the Camel (19), Thompson says that its fibres seem to be 

 continued into the stylo-pharyngeus muscle, but this we did not 

 notice in any other animal. 



The nerve-supply is the facial. 



Text-fig. 88. 



Hyoid muscles of the Uuiker-bok. 



f)' I Double Stylo-glossus. 



3. Stylo-pharyngeus. 



4. Stylo-hyoid. 



5. Masto-styloideiis. 



6. Digastric (Depressor maudibiili). 



7. Stylo-hyal bone. 



8. Tympanic bone. 



9. Paroceipital process. 



Stylo-hyoid. — This muscle usually rises by tendon from the 

 posterior luberosity at the upper end of the stylo-hyal, and runs 

 downward and forward to be inserted into the base of the cerato- 

 hyal. In the Hippopotamus, Grratiolet and Alix (III.) say that it 

 rises from the paramastoid process, and in Cuvier and Laurillard's 

 plate of this animal (I.) it apparently has the same origin. In 

 the Hyrax also we (68) agree with Mivart and Murie (67) that it 

 arises from the paramastoid process. It is always supplied by 

 the facial nerve, and we believe that the masto-styloideus is the 

 proximal part of this muscle, which is cut off by the projection of 

 the stylo-hyal bone so characteristic of most Ungulates (see 

 text-fig. 88). This belief is strengthened by the fact that in the 

 Hyracoidea, where the stylo-hyoid rises from the paramastoid 

 process, the masto-styloideus is absent, and we await future in- 

 vestigations of the muscles of this region of the Hippopotamus 

 with interest. Thompson's assertioji that some of the fibres of 

 the masto-styloideus are continued into the stylo-pharyngeus in 



^ We hare no definite account of it in tiie Hippopotamus. 



Pboc. Zool. SOC.--1901, Vol. II. No. XLIV. 44 



