EEPTILES. 291 



walking. To this family are referred the foot-marks found on 

 slabs of new red-sandstone in the quarries of Corn Cockle 

 Muir, Dumfries-shire.* Bones of Testudo have been found 

 in the great oolite of England, the chalk of America, and 

 in the tertiary strata of France. Fragments of an extinct 

 genus, fyTeqalochelys, have been discovered in India by 

 Cautley and Falconer, in the newer tertiary bed of the 

 Himalaya. The bones justify the inference, that the cara- 

 pace of this giant was about twenty feet in length; the 

 remains of tortoises have been found by "Weiss with the 

 bones of the megatherium, in South America. 



2nd Family. The EMYSID^, or Marsh Tortoises, have 

 the carapace of an oval form, solidly articulated, but more 

 depressed than that of the Testudina3. The toes, four to 

 five in number, are long and distinct, and united at then 1 

 base by a membrane to adapt the extremities for swimming. 

 This family contains extinct and living genera. The extinct 

 genera are IdiocJielys, from the Oxford stage of Kelheim; 

 jEurygtcrmm, from Solenhofen, and Tretosternon, from the 

 Purbeck stage of the wealden. "We know extinct species 

 of Emys from the Kimmeridge clay of Soleure in France, 

 and from the wealden of England and Germany. Five species 

 of the same genus are found in the eocene stage of Sheppey. 

 Fossil species of Platenvys are found in the Kimmeridge 

 stage of England and Switzerland. Two species have been 

 obtained from the eocene stage of Sheppey, and from the 

 tertiary beds of the same age in France and Belgium. 

 Species of Chelydra and Cletnmys are found in the upper 

 tertiaries of the continent of Europe. 



3rd Family. The TRIOJSTXIDJE, or fluviatile tortoises, 

 have the body flat, the carapace and the plastron large, much 

 depressed, and united by cartilage, deprived of horny plates, 

 and covered with a soft integument. The plastron is incom- 

 pletely ossified, and the original cartilaginous state of the 

 margin of the carapace is persistent through life. The feet 

 have five toes, of which three only have nails ; hence the 

 name, trionyx. The two unarmed toes support a webbed 

 membrane for swimming. All the living Trionyxida3 are 



* Sir W. Jardine, Rep. Brit. Association, refers these foot-marks to two 

 genera, Ckelichnus and Herpctichnus. See the heautiful illuminated plates 

 in his "Ichnology of Annandale." 



u 2 



