MUSCULAR SYSTEM OF MAMMALIA. 



23 



thereto. Here a mid-line of separation 

 appears, and the muscle bifurcates into 

 two flat fasciculi, which are inserted 

 into the angles of the basihyal. 



The sternothyroidei, fig. 9, /?, p, 

 come off from the sixth, seventh, and 

 eighth sternal bones, and from the 

 seventh and eighth sternal ribs near 

 their articulations therewith. The in- 

 terthoracic extent of these muscles is 

 six inches. Behind the manubrium 

 the left muscle sends off a small fasci- 

 culus of fibres to the right one, and 

 the right reciprocally to the left. 

 Where the decussation takes place 

 there is a tendinous intersection at the 

 fore part of the muscle. In advance 

 of the interchange of fasciculi the ster- 

 nothyroidei diverge and emerge from 

 the chest, beyond which cavity they 

 are fleshy throughout their extent, and 

 are inserted into the lower and fore 

 part of the thyroid cartilage. 



Sternoglossus, ib. g, /. This remark- 

 able muscle arises fleshy from the 

 lateral border of the dilated xiphoid 

 and last sternal bone, arid from its 

 junction with the last two true ribs. 

 Linear tendinous intersections mark 

 the part of the muscle within the chest. 

 Emerging from beneath the manu- 

 brium, it advances as a flat fleshy mus- 

 cle. Opposite the hyoid it is perforated 

 by a lingual artery, between four and 

 five inches in advance it is perforated 

 by the lingual nerve, h, and here its in- 

 ferior stratum is resolved into flattened 

 fasciculi of fibres which decussate or 

 combine with those of the opposite 

 muscle. About six inches in advance 

 of the basihyal these fasciculi spread 

 over a dilated membranous portion 

 of the buccal cavity, at the lower part 



a 



1 



Ili 



X - 



y\ 



of Tongue.. Great Anteater. 



