448 



JacksorCs Anatomical Description 



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sive a name for the species^ and also that of the nails is 

 well represented in Plate X. and is strongly characteristic 

 of the Land Tortoise. 



It may here be mentioned, that the following description 



applies more particularly to the female. 



One of the Eyes 



form globular; about 



three fourths of an inch in diameter ; nine ossific plates in 

 anterior part of sclerotic coatj slightly convex on the 

 external face, overlapping irregularly and varying in width 

 from two to three lines (a line being considered as the 

 . twelfth of an inch). Lachrymal glands large and granu- 

 lar. Lower eyelid much_ deeper than the upper. 



The Ear had a single ossiculum^ long, slender and 

 funnel-shaped at its inner extremity, such as is generally, 

 if not always, found in this order of reptiles. The faculty 



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of hearing is denied by Capt. Porter, but there was 

 abundant proof to the contrary in our two specimens 

 during life, and the observation was fully confirmed by 

 dissection. 



The Jaws were very powerful, being formed of a 

 dense, horny substance, and made up of serrated ridges 

 corresponding with grooves which fit perfectly into each 

 other like the blades of scissors. They measure in thick- 

 ness, or from without inwards, from one half to nearly an 

 inch ; vertically, one and a half inch in front, but dimin- 

 ishing to one half, towards the articulation. The upper 

 surface of the lower jaw consists of a deep, well defined 

 groove, bounded on either side by a sharp, high ridge, 

 and terminating anteriorly in a stout conical tooth which 

 IS very much larger than any in the upper jaw ; the outer 

 ridge is serrated upon the sununit and upon the outside 

 as far down as where it shuts into the upper jaw ; it is 

 rough from numerous, fine, projecting points and lines ; 



