OF REPTILES AND BIRDS. g 



the ventral side of the tongue, and maintains that position throughout figs. 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 ceratoglossi gradually taper 

 towards the tip, while the other muscles increase in relative 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 terminates 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 Ungualis 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, fig. 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 ceratoglossi. The Ungualis is cut up 

 by muscular septa, formed by the transversi and verticalis. 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 transversus superior, and inserted ventrally directly into the 

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

 also the two transversi inferiores. 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 transversi can be best described together, although at the posterior extremity of 

 the tongue they are absolutely distinct, fig. 10. In Eutaenia sertalis exactly the same 

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

 the three transversi 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 

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

 from the ventral side, and those which correspond to the transversi inferiores 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. 



Prom 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-vaginii ; and second by the elongation of the tongue by 

 the contraction of the transversi and verticalis. 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 



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



