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tabe. This muscle may, by contracting round the tube when it 

 rests on the style, prevent its revolving on that bone, and thereby 

 make steady the prehensile portion, and adapt it for the ordinary 

 uses of the tongue in mastication. Two retractor muscles (Fig. 5. 

 l.I.) arise one from either side of the back part of the annular mus- 

 cle, and thence pass to its upper surface, where they meet under the 

 mucous gland, to be inserted into the bottom of the pouch. They 

 may contribute to the more effectual security of the prey by deep- 

 ening, and closing the pouch upon it, a change which this part evi- 

 dently undergoes while the organ is retiring into the mouth. 



To the second portion of the tongue I have given the name 

 erectile, on account of the resemblance which I conceive it bears 

 to the other erectile structures of animals. It is placed between 

 the prehensile portion and the os hyoides, and exhibits remark- 

 able changes in bulk under different circumstances. When 

 drawn from the mouth after death, which it may to the length of 

 five or six inches, (Fig. 4. H) it presents itself as a slender chord, 

 so flexible and soft as scarcely to be felt when caught between the 

 fingers, and to appear little adapted for the purposes to which it is 

 applied. During life, while the tongue rests in the mouth, this 

 portion occupies an exceedingly small space, (Fig. 2, 7, H.) 

 but when projected in the pursuit of insects it becomes greatly in- 

 creased in dimensions (Fig. 3, H), and appears to be wholly the 

 seat of that change which the organ undergoes in its elongation. 

 Its structure is complex and peculiar. A fine transparent mucous 

 membrane, which is continuous posteriorly with tliat which hues the 

 mouth and throat, and anteriorly passes over the prehensile portion, 

 encircles it on all sides. The hyo glossi muscles occupy its lateral 

 surfaces. They are round and thick posteriorly at their origin from 

 the os-hyoides, and become thin and flat as they advance forwards 



