3 1 4 ELEMENTAR Y ANA TO MY. [LESS. 



cornua being so much greater than in the human structure. 

 It may be attached above to the par-occipital process, as in 

 the Horse, or to the posterior part of the lower jaw, as in 

 some Birds, e.g. the Fieldfare. 



The stylo-glossus and stylo-pharyngeus present few dif- 

 ferences in Mammals, except that the former may take origin 

 from the paramastoid process (as in Hyrax), or low down on 

 the anterior cornu, as in Ruminants. 



The mylo-hyoid even in Mammals may be quite discon- 

 nected with the hyoid, and it may be exceedingly elongated 

 and divided into several antero-posteriorly successive parts, 

 as in the Great Ant-eater. The hindmost part may, even 

 in man's class, take origin from the sides of the occiput, as 

 in the Echidna. It may be very large, as in Menopoma 

 (Fig. 282). 



The genio-hyoids are very constant, existing down to 

 Fishes. They maybe inserted into the cornua (not the body) 

 of the hyoid, as in Birds and Fishes, or into fascia bounding 

 the body of the hyoid beneath, as in Menopoma, or into the 

 uro-hyal, as in Menobranchus. 



The hyo-glossus of man, arising as it does from three parts, 

 might be expected to present (as is the case) variations in 

 other animals in accordance with the varying development 

 of its three points of origin, namely, the body, and the lesser 

 and greater cornua respectively of the os-hyoides. 



By a yet further modification the hyo-glossus may be de- 

 tached from the hyoid and blended with a sterno-hyoid also 

 detached from the hyoid, so that we have an enormously long 

 muscle entering into the substance of the tongue, but taking 

 origin as far back as the xiphoid cartilage. Such is the case 

 in the Great Ant-eater, where the hyo-glossi are reinforced 

 by small muscles springing from the anterior cornua. Both 

 lateral and median muscles exist in most Birds, and lateral 

 muscles (i.e. from the cornua to the tongue) exist in Reptiles 

 and the Frog, and even in some Fishes, all but tongueless 

 as are the last-named animals. 



The genio-glossus may take origin from the sides of the 

 mandibular rami instead of from the symphysis, as in Ser- 

 pents, or it may have two origins (one from the symphysis and 

 one from the side of the mandible), as in the Great Ant-eater. 

 This muscle may be wanting altogether, as in Fishes, and 

 even amongst Birds while nevertheless it exists not only in 

 Reptiles but also in Batrachians (e.g. the Frog, Salamandra, 

 and Menobranchus). 



