12 MINOT ON THE TONGUE 



suppositions are correct it is to. be expected that this nerve will be found to be the glos- 

 sopharyngeus, which has a similar distribution in mammals. 



The middle nerve, fig. 1, B, I have also not succeeded in following satisfactorily, but I 

 consider it probable that it is continuous with the nerve marked B, figs. 4-11. This 

 latter lies in the midst of the M. transversus superior, and runs straight forward to the 

 fork, without giving off any branches ; but there, beginning to divide and sub-divide, it 

 entex's the fork of the same side to which it is distributed. The nerve is accompanied 

 through the body of the tongue, by an artery of about the same diameter as itself. The 

 nerve and artery are surrounded by connective tissue which diAddes the Muse, transversus 

 superior into two parts {cf. figs 9-7). The tissue on either side is separated from that on 

 the other by the vertical muscle, so that the transverse partition is incomplete. As with 

 the first nerve so with the second ; we make from its distribution, which is to the tips of 

 the tongue, an inference, namely : that it is homologous with the mammalian lingualis. 



II. Tongue of Ameiva. 



The tongue of Ameiva surinamensis, is, in proportion to the size of the animal, both 

 shorter and much thicker than that of the snakes. It tapers from the base and divides 

 into two forks, each of which consists of a basal portion with corneous epithelium, and a. 

 more delicate and almost thread-like, darkly pigmented tip. The main body of the tongue 

 is flattened and expanded above, the upper surface being entirely covered by diamond 

 shaped scales, so disposed as to form rows extending from the sides obliquely backwards. 

 These rows are not perfectly regular. The effect produced, in the alcoholic specimen I 

 have examined, is of the back of the tongue being crossed by two oblique systems of pale 

 lines. The scales also extend forwards to the tips, and downwards a little Avay to the 

 underside of the tongue, which is smooth, but with two longitudinal ridges, separated by a 

 median depression, and corresponding to the large ceratoglossal muscles. On the outer 

 side of each ceratoglossal ridge is a longitudinal furrow, homologous with the lateral 

 furrow of the snake's tongue, which divides the smooth ventral, from the upper scalv 

 surface. At the anterior end of the under side there are two scales, attached by their 

 posterior and median edges, but otherwise entirely free. They lie one at the base of each 

 fork. As shown by transverse sections they are duplicatures of the epidermis, supported 

 by an extension of the cutis. Upon the outer, i. e., ventral surface of these scales, both 

 the corneous and mucous layers of the epithelium are considerably thickened. What the 

 possible function of these singular structures may be, I cannot surmise. The posterior 

 part of the underside of the tongue serves for its attachment to the floor of the mouth. 

 The division of the forks into two parts is striking, and the horny epidermis must prevent 

 any bending or change of length in the basal part. The formation of small scales on the 

 body of the tongue permits freedom of motion. The last mentioned scales are quite 

 peculiar, being fungiform, with a broad flat horny top and a thick stalk, Avhich has a thick 

 dermal core, with numerous ramified pigment cells (fig. 12). From the above description 

 it is evident that the tongue of Ameiva differs considerably from that of snakes ; neverthe- 

 less the arrangement of the muscles within the free part is almost identical in both, the 

 principal difference being, in the proportions. 



