COLOSSOCHELYS ATLAS. 365 



true land-tortoises. A like result followed the examination 

 of the extremities, which, as exhibited in the remains of the 

 humerus, femur, and ung-ual phalanges, were seen to be con- 

 structed exactly on the plan of Testwdo, with columnar legs 

 and truncated club-shaped feet, as in the proboscidean 

 Pachydermata. The same direction of aflB.nity was observed 

 throughout the confirmation of the head. The only portions 

 of the skeleton from which more or less direct evidence was 

 not derived were the neck and tail vertebi-se, of which there 

 were no specimens in the collection. The general result of 

 the examination showed that the Golossochelys Atlas was 

 strictly a land-tortoise in every part of its bony frame ; and 

 the impressions of the horny scutes proved the like in regard 

 to the arrangement of its dermal integument. 



The principal distinctive characters were found in the 

 sternum, which is enormously thickened at its anterior ex- 

 tremity, along the united portion of the episternal bones, and 

 contracted into a narrow neck, so that the width of the com- 

 bined episternals does not much exceed their thickness ; this 

 thickened portion bears on its under side a deep massive 

 cuneiform keel, which terminates upon the commencement of 

 the entostemal piece. There is more or less thickening of 

 this part in all the species of Testudo, and the amount of it 

 is very variable in different individuals of the same species ; 

 but there is nothing approaching the same degree of con- 

 traction in reference to the thickness, nor aught like a 

 developed keel, in any of the existing land-tortoises which 

 we have either had an opportunity of examining, or seen 

 described in systematic works on the tribe. The keel in the 

 fossil is feebly shown in the young animal, but strongly 

 marked in the adult. Conceiving that generic distinctions 

 are only legitimate in the case of well-defined modifications 

 affecting some of the leading characters in the organization of 

 an animal, we do not consider ourselves warranted in attaching- 

 a higher systematic importance to the Golossochelys than as 

 a subgenus of Testudo, which may technically be defined 

 thus (the distinction resting mainly on the form of the 

 sternum) : — 



Subgen. COLOSSOCHBLTS. 



Testa solida, immohilis, sterna antice in collum valde incrassa- 

 tum, suhtus carina crassd cuneiformi instructum, angustato, 

 — Testudo terrestris, statura et mole ing-ente (inde 

 nomen KoXoaaos et ^sAus) sui tribus prodigium ! Olim in 

 Indise Orientalis provinciis septentrionalibus degebat. 



Golossochelys Atlas. 

 The first fossil remains of this colossal tortoise were dis- 



