OF REPTILES AND BIRDS. g 



the ventral side of the tongue, and maintains that position throughout fio-s. 5-9. The 

 single fibres of the muscle are at first some distance apart, fig. 9, but they soon become 

 more compact in the free part of the tongue, fig. 7. The ceratoglossl gradually taper 

 towards the tip, while the other "touscles increase in relatioe bulk. Towards the fork the 

 two muscles under consideration divaricate and each, greatly reduced in size, enters the 

 tips ^ of the same side, fig. 5, and termlnatcis in a tendon, which first appears on the 

 under side of the muscle not far from the base of the fork, and extends as the direct 

 continuation of the muscle forwards in the tip. 



The Ungualls is confined to the free part of the tongue ; it begins near the point of 

 attachment, fig. 1, a, occupies the dorsal portion of the muscular core, above the trans- 

 versus superior, fig. 8, and extends forwards, at first increasing in diameter, fio-. 7, then 

 slowly diminishing as the tongue tapers, fig. 6. At the fork, fig. 9, it divides into two 

 portions which become the superior longitudinal muscles of the tips, in which they are 

 much more voluminous than their antagonists, the ceratoglossl. The Ungualls is cut up 

 by muscular septa, formed by the transversl and vertlcalls. These septa are more prom- 

 inent in the tips than in the body of the tongue. 



The verticalis is at first, i. e., posteriorly, entirely distinct, fig. 10, v, arising dorsally 

 from the lower side of the traiisversus superior, and inserted ventrally directly into the 

 common fascia of the lingual muscles, thus separating not only the two ceratoglossl, but 

 also the two transversl mferlores. The inferior attachment is retained up to the fork of 

 the tongue, but is there lost, the lower end of the vertical muscle becoming gradually 

 more and more interwoven with transverse fibres. The upper end on the contrary soon 

 begins to interlace with the superior transverse muscle, fig. 8. 



The trcmsversl can be best described together, although at the posterior extremity of 

 the tongue they are absolutely distinct, fig. 10. In Eutaenla sertalls exactly the same 

 relation exists, as will be recognized by comparing cut 1, with fig. 10. Further forward 

 the three transversl fuse around the base of the free part of the tongue, fig. 9. They 

 form a continuous layer of annular fibres. The upper segment corresponding to the 

 transversus superior attains predominance, and is divided into two portions by the nerves, 

 (lingual ?) figs. 9, 8, 7, B, and the arteries and tissues which accompany them. Still 

 further forward, the upper segment is forced down into the middle of the core, by the 

 Ungualls above it, fig. 8. At the same time the transverse or annular fibres disappear 

 from the ventral side, and those which correspond to the transversl infer lores assume a 

 vertical position at the sides of the tongue, fig. 7. Before the forking takes place, the 

 intermingling of the various transverse and vertical fibres becomes so complex that the 

 component muscles cannot be distinguished, there being besides many oblique fibres, two 

 systems of vertical and transverse fibres distinguishable, fig. 6. 



From the disposition of the muscles, we may conclude that the tongue is thrust out, 

 first by pulling forward the base of the tongue by the genio-hyoid portion of the con- 

 strictor, and especially by the genio-vaghili ; and second by the elongation of the tongue by 

 the contraction of the transversl and vertlcalls. The retractors are, first, the longitudinal 

 Ungualis and ceratoglossi, and second, the retractors of the hyoid, namely the vertebro- 

 and costo-hyoid portions of the constrictor, and Dumeril's "peaussier" (paniculus), the 



'"Tip" is used to designate the two forks or brandies of the tongue, and refers to the whole branch, and not to the extremity. 



