190 



IH. R. II. BURNE ON TUE 



The Muscles of the Tongne and Pharynx. 



The muscles of the tongue conform in general to the common 

 Ruminant type, but in the details of their arrangement and 

 individual development disclose more points of agreement with 

 the Giraffe than with any of the other Ruminants examined. 

 ' A comparison of the accompanying figures (figs. 1, 3, 4, 5, 6) 

 shows more i-eadily than a verbal description how close the 

 similarity between the Okapi and Giraffe in respect of these 

 muscles is. Attention may, however, be drawn to the following 

 particulars. 



Digastric, Mylohyoid, Geniohyoid, and Genioglossus Muscles. 



Blending of the various muscles in the floor of the mouth to a 

 varying degree is typical of Ruminants in general. In the 

 majority, if not in all genera, the anterior belly of the digastric 

 muscle and tlie mylohyoid are so closely united that where they 



Text -figure 3. 



Outline of the tongue and pharynx of a Giraffe, for comparison with text-fig. 1. 

 , Lettering as in text-fig. 1. 



blend in the superficial sheet of the mylohyoid it is impossible to 

 distinguish the one from the other. The deeper muscles (genio- 

 hyoid and genioglossus) are, as a rule, more independent. 

 Generally the former has a weak fibrous attachment along the 

 central line of the mylohyoid, and very occasionally (e.g. Antilope 

 cervicapra) it unites with the genioglossus close up to the sym- 

 physis menti, but as a rule it is a well-developed paired muscle 

 independent of its neighbours. 



In the Okapi and Giraffe, not only is the association of the 

 digastric and mylohyoid peculiai-ly intimate, but there is also a- very 

 close fibrous union between the deep layer of the mylohyoid and 

 the geniohyoid and a blending of the geniohyoid and genioglossus. 



The geniohyoid is also very much I'educed in both these 



