THE GREAT TORTOISES. 249 



Laying eggs, the Chelonia have them of a calcareous nature outside in the Land Tortoises and 

 fresh-water kinds ; buj the Turtle's eggs are leathery, or like parchment to the touch. The construction 

 of the egg-producing organ greatly resembles that of Birds ; and it is only necessary to state that the 

 internal structure of the egg and the development of the young in its early stage differ in no very 

 essential circumstances from those of the Bird. The carapace and plastron appear before the egg is 

 broken by the outcoming Chelonian. 



There is a wonderful amount of vitality in the Cheiomans, and, indeed, in many other 

 Reptiles. Some can live for many months, and it is said years, without food, and it is well known that 

 movements and indications of life remain for a considerable time after the head has been removed from 

 the body or the brain from the head. Their lives are veiy much the same year after year and ge- 

 neration after generation ; their passions are cold-flooded, and there are no permanent displays of the 

 affections. Hence the brain and spinal nervous system are less developed than in Birds, and they are 

 small for the size of the head and body. The surface of the rather long brain is smooth, and there is 

 a projection in front the olfactory lobe which is hollow ; the optic tubercles are rounded, and are 

 separated by a deep fissure ; the cerebellum is nearly hemispherical, and the fourth ventricle is well 

 developed. Finally, the sympathetic or organic system is feebly developed in the Chelonia. 



FAMILY I. THE TORTOISES. -THE LAND CHELONIANS.* 

 These have the carapace and plastron bony, and covered with shelly plates, and 

 the buckler as a whole is swollen above. They can retract the head, neck, and 

 extremities within its covering, and they live on land. 



THE GREAT LAND TORTOISES. 



When Mr. Darwin visited the Galapagos Islands, he saw the relics, as it were, of 

 a family of huge Tortoises, which lived there in abundance a few years before, and was 

 able to verify many interesting facts which had been recorded by Porter, in his 

 " Journal of a Cruise Made to the Pacific Ocean in 1813." Porter noticed the deafness 

 of the huge creatures, and, like former voyagers, was impressed with their enormous 

 size, with the long necks of some, and with their quick sight and ponderous move- 

 ment. He stated that some of the Tortoises captured by him weighed from 300 Ibs. BRAIN OF CHE- 

 to 400 Ibs., and that on one island they were five feet and a half long, four feet IONIAN. 

 and a half wide, and three feet thick in the body. They walked with the body about ^Pcerebrum'T?! 

 a foot from the ground, and the females seemed to preponderate. It is quite evident cerebellum; 1 '&, 



. t-plnal Cord. 



from Porter's narrative that several kinds lived in the islands, those of one island 

 differing from those of another, but all being of the same group of Tortoises. He expatiates on 

 the luscious and delicate food that the long-necked and small-headed and other kinds supply, and 

 notices their ability to last long without food. After Mr. Darwin's visit the progress of extirpation 

 went on, and in eleven years Mr. Seeman, naturalist on board H.M.S. Herald, found that on one 

 island there were no longer any Tortoises, and that everywhere they had diminished in number. 

 At the present time it is most probable that the gigantic Tortoises are vei-y rare where they 

 were formerly so abundant. There were five species there a few years since. 



These Galapagos Tortoises were of several kinds, each inhabiting especial islands in the Archi- 

 pelago, and they can be recognised in museums and in the few living specimens which have been 

 brought to Europe by the black colour of the shell, the thin condition of the bony carapace, the 

 general lightness of the huge buckler, and by the usual front plate being absent, so that their long neck 

 can be raised up, carrying the head above the level of the body. The legs are long, and there is a 

 remarkable plate or scale on the inner side of the elbow. 



They have flat-looking and small heads, and usually there is a very decided crest of bone at the 

 top and back of the skull. Dr. Giinther described four important species of this group, and states that 

 in James Island, Testudo elephantopus and Testudo niyrita were the only kinds, and perhaps only the 

 first-named; and he has evidence to prove that King Charles Island was inhabited by Testudo ephippium, 



* Testudines. 



