REPTILES 49 



Galapagos Testudo (genus Elephantopus of Gray). — Nuchal 

 plate absent; a pair of gular plates; frontal region of the skull flat; 

 fourth cervical vertebra biconvex. In T. galapagoensis the third 

 cervical vertebra is biconvex. Nine described species peculiar to the 

 Galapagos Archipelago. 



Allied most closely by the characters of the skulls and vertebrae to 

 the tortoises of the Mascarenes (Mauritius and Rodriguez Islands) 

 from which they are separated by the divided gular plate. 



The following account of the habits of the Galapagos tortoises is 

 based on observations made on the three species collected, viz., T. 

 microphyes, T. vicina and T. ephippium. 



Their food consists of various species of grasses and cactus (^Opun- 

 tia). • During the rainy season and in the moist portions of the islands 

 the year round grass forms their chief food, especially a large, woody 

 stemmed, perennial species. During the dry season in the arid portions 

 of the islands, as at Tagus Cove, Albemarle, and on Duncan Island, the 

 Opuntia h&comGS quite an important food plant. The green succulent 

 leaf-like stems of this cactus and its fruit, the "prickly pear," are eagerly 

 devoured by the tortoises regardless of the sharp spines with which 

 they are armed. One specimen collected near Tagus Cove had the 

 whole palate and pharynx bristling with cactus spines from which 

 there was apparently no suffering. The juicy cactus stems supply the 

 tortoises with the necessary water in the dry regions where springs are 

 absent and thus make possible its existence in such localities. Cactus 

 seems to be preferred, when it can be easily secured; all the tortoises 

 we took on board the schooner would take no other kind of food 

 except when compelled by hunger. The Opuntia are tree-like in 

 habit, growing usually to a large size and it is only the young and 

 smaller plants that are within reach of the tortoises. Grass can be 

 secured much easier and it is perhaps due to this fact that it forms a 

 larger proportion of their food. 



The tortoises do a great deal of apparently unnecessary travelling 

 and though slow are so persistent in their journeys that they cover 

 several miles a day. Most of the travelling is done early in the morn- 

 ing and late in the afternoon, the hot hours of noon being spent in the 

 shade of some bush wallowing in the damp soil. The wallowing 

 probably cools them and incidentally relieves them of a few of the 

 numerous wood ticks {Amblyofna pilosu?n) which infest them at the 

 joints and wherever the skin is thin enough to allow them to pierce it. 

 After heavy rains they delight to wallow in the mud. They are very 

 determined travellers and when once started in a certain direction no 



