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ingly short in the land-tortoise ; moderately long, and rather 

 equal, in the fresh-water tortoise and the chelydes ; and, in 

 the soft tortoises, it is to be observed, that three only of the 

 toes bear talons. 



The head of the chelydes is known by its flatness, and by 

 its transverse jaws ; that of the sea-tortoise, by the temporal 

 region being covered by a bony vault ; and that of the soft 

 tortoises, by the long and bowed fringe. 



The ossification of the intervals between the ribs is per- 

 formed slowly; and, proceeding from the middle part to- 

 wards the edge, it is terminated generally later than that of 

 the ribs themselves. 



The fossil remains of these animals are, with difficulty, refer- 

 rible to even the several genera into which they are divided. 



It is only, of course, the hard parts of the animal which 

 are preserved by petrifaction : hence the bones of the toes, 

 losing their connecting medium, become detached, and it 

 will only be by their forms that any conjecture can be made 

 whether they were distinct, clubbed, or webbed. In all 

 those species, too, of the genus emys, in which the carapace 

 was in a soft state, some ambiguity will arise, since it will 

 not be always easy to determine whether the irregularity or 

 apparent imperfection of form has depended on the original 

 structure of this part, or has proceeded from violence. 

 Thus, the fossil remains of one of these animals, found in 

 the neighbourhood of Melsbroeck, near Brussels, was de- 

 termined, by Lacepede, to have belonged to testudo my das, 

 Linn.; and Camper describes the back of a fossil tortoise 

 which was four feet in length and only six inches in width . 

 the preserved part in this, and similar specimens, being the 

 hard and osseous part of the animal which extended along 

 the vertebral column, the difficulty having arisen from the 

 loss of the coriaceous or horny covering with which, in that 

 species, the remaining part of the superior covering had 

 been formed. 



