THE GREAT ANTEATER. 311 



bone for the greater part of its length, not, however, extending to either 

 of its extremities. Along the anterior (free) border of the ascending 

 part, at the point where it is in contact with the ducts and the deep 

 part of their muscular ring, is developed a strong tendinous edge (s.h.m.t.), 

 the " commissural tendon " of Owen. 



The muscular fibres inserted on this and attached to the stylohyal 

 (ceratohyal of Owen's nomenclature) are described by that author as the 

 " cerato-hyoideus" whilst Pouchet more correctly applies to it the name 

 of " stylo-hyoideus" the rest of the muscular arrangement here described 

 forming, as already stated, the " constrictor scdivaris " of both authors. 



It appears to me that the whole muscle may be more correctly con- 

 sidered as the stylo-hyoideus^ which has developed this remarkable course 

 round the submaxillary ducts in order to aid the ejaculation of the saliva 

 therein contained by the constriction, on contraction of the muscle, of 

 their walls between the circularly-disposed fibres surrounding them and 

 the tendon developed on its anterior margin. 



In the genus Tamandua* (Plate VIII. fig. 2) there is no special mus- 

 cular envelope developed round the ducts in this position. The most 

 posterior fibres of the mylo-Tiyoideus (m.h 1 ) arise from the posterior end 

 of the stylo-hyal bone, running inwards and forwards, and blending 

 internally with the genio-hyoid. To this point also run backwards and 

 inwards the fibres of a narrow flattened muscle (s.h. m\ which crosses 

 the hyoid origin of the mylo-hyoid superficially, and, as it arises from 

 the stylo-hyal bone, must be considered to represent a stylo-Jiyoideus. 

 At the point where it meets the genio-hyoid and mylo-hyoid, all three 

 muscles become closely connected together, the stylo-hyoid developing 

 here an anterior tendinous edge (s.h. m. t). Between this tendon and 

 the conjoined mylo-hyoid and genio-hyoid run the three ducts of the 

 submaxillary gland, so that contraction of these muscles here also serves 

 a purpose similar to that produced by the more specialized arrangement 

 found in the larger species. 



[P.S. July 13, 1882. I have found the disposition of the salivary 

 ducts and the arrangement of the stylo-hyoideus muscles exactly the 

 same as those here described in a third specimen of Myrmecophaga just 



dead. w. A. p.] 



EXPLANATION OF PLATE VIII. 



Fig. 1. Dissection of the left suprahyoidean region of Myrmecophaga jubata, to 



show the course and relations of the stylo-hyoideus muscle, s.h, stylo- P. Z. S. 1882, 

 hyal ; e.p, epihyal ; c.h, cerato-hyal ; b.h, basihyal ; t.h, thyro-hyal ; s.h. m', ? ^0^- 



* Cf. Duyernoy, Mem. Strasb. 1830, " Meruoire sur la laugue" &c., p. 3. 



