390 ANATOMY OF VERTEBRATES. 



three upper rings of the trachea. The retractor pharyngis is a 

 slender longitudinal muscle, arising from a fascia connected with 

 the origin of the scalenus, runs along the outer side of a long 

 slender gland, and then passes forward to the outer side of the 

 crico-pharyngeus, where it bends backward, slightly expands, and 

 appears to blend with the contiguous fibres of the crico- and 

 tkyro- pliaryngei. In the Armadillo (Dasypus 9-cinotus) the 

 epiglottis projects through the arch of the soft palate, in the 

 middle of which there is a thickened part like a rudimental 

 uvula. 



The mouth is remarkable for its small relative size in the Mana- 

 tee. In a specimen with a head eighteen inches long and fifteen 

 inches deep, the oral opening was only three inches from angle to 

 angle. The anterior border of the premaxillaries, covered by a 

 callous gum, projects beneath the thick upper lip, and the horn- 

 clad symphysis of the mandible makes a similar projection above 

 the under lip. 



The mouth is relatively small in the Elephant ; the under lip 

 alone is free, and is produced into a pointed form ; the upper lip 

 blends with the nose, and is, therewith, produced into the re- 

 markable prehensile appendage characteristic of the proboscidian 

 order. As it chiefly ministers to the mouth, conveying thereto 

 the aliment, it will be described in the present section. 



The proboscis of the full-grown Elephant forms an elongated 

 cone of four or five feet in length, gradually tapering from the 

 root towards the point, which is terminated by a kind of thumb- 

 like appendage which is endowed with exquisite sensibility, so as 

 to be useful in picking up the smallest objects. It is perforated 

 lengthwise, by a double tube, formed by a strong tendinous mem- 

 brane, lubricated by the secretion of innumerable mucous crypts. 

 The membranous tubes are continued upward as far as the bony 

 nostrils ; but, a little before their junction with the latter, they 

 form two curves, the nasal passages being closed at this point by 

 a cartilaginous elastic valve, which may be opened at the will of 

 the animal, but closes by its own elasticity when the muscles 

 which open it cease to act. The interval between the membranous 

 tubes and the skin of the proboscis is filled up with a thick layer 

 of muscular substance composed of several sets of fibres, and with 

 sclerous tissue. 



The nasal passages may be observed to be not in the centre of 

 the trunk, but nearer the anterior surface : the muscles before 

 them pass in a radiating direction to the circumference of the 

 proboscis ; those which are immediately behind the nasal passages 



