2*2 



PALAEONTOLOGY 



whole world ; and all the eocene Chelones are extinct. One 

 of them (G. gigas, Ow.) attained unusual dimensions ; the 

 skull, now in the British Museum, measures upwards of a 

 foot across its hack part. The estuary genus Trionyx (soft 



Fig. 82. 

 1'/ in roster non emarginatum i Purbeck . 



turtle) is represented by many beautiful species in the upper 

 eocene at Hordwell ;t the fresh-water genera Emys and Platemys 

 by as many species, both al Sheppy and EordwelL In the 

 pliocene of G^ningen remains of a species of GJidydra have 

 been discos ered : this generic form is now con lined to America. 



* The upper end of the femur from Sheppy, in t. xxix. of Monograph of 

 Fossil Reptilia of the London ''lay. Palseontographical Society, 1850, belongs 

 to thin species, See also " Hist, of Brit, F"ss, Reptiles," pp 10-40, pis, 1-22. 



f Op. cit., pp. ">h 60, pis. 26 33 



