THE GALAPAGOS TORTOISES. 2f)9 



smoothness: such species are T. nigra, T. microphyes, and T. macrophyes. 

 Testudo vicina, T. nigrita, and T. elephantopus and its varieties T. abingdonii, 

 T. becki, and T. duncanensis all slough when young and afterward retain the 

 striae as if no sloughing took place. 



Evidence that may be adduced in regard to the shortness of time since 

 separation from one another is seen in the affinities of the tortoises; likewise in 

 this connection there is no lack of confirmation for the statement that the species 

 of various islands have been modified by importations from others. The early 

 specimens now in museums, nearly all of them without known locahties, are 

 very difficult to place even with the aid of the considerable numbers in recent 

 collections from certain islands. Changes have occurred in the last century 

 that make some of the descriptions quite contradictory. Porter, 1815, in his 

 Journal describes the tortoises from James Island (San Salvador) as round, 

 plump, and black as ebony, their shells ''sometimes remarkably thin and easily 

 broken but more particularly so as they become advanced in age ; when, whether 

 owing to the injuries they receive from their repeated falls in ascending and 

 descending the mountain, or from injuries received otherwise, or from the course 

 of nature, their shells become very rough, and peel off in large scales, which 

 renders them very thin and easily broken." Van Denburgh, 1914, in his mono- 

 graph, p. 321, says "The James Island tortoise is a very large, heavy, thick- 

 shelled species which resembles most closely the tortoise of Jervis Island [Ra- 

 bida] and the Testudo vicina of southern Albemarle. It is somewhat intermedi- 

 ate between the saddle-backed and dome-shaped races. The front of the 

 carapace is high, but the middle of the back rises still higher. There is but 

 little narrowing of the front of the carapace." Porter's description was made 

 a century earher than Van Denburgh's. Porter's description of the tortoises 

 of Santa Maria (Charles) and Espaiiola (Hood) applies a little better to T. 

 elephantopus Harlan than to T. nigra Dum. & Bib. now known to be the Charles 

 Island species, of 1835. ''The form of the shell of the latter is elongated, turn- 

 ing up forward in the manner of a Spanish saddle, of a brown color and con- 

 siderable thickness." How much the differences are is apparent on comparing 

 with the descriptions and plates below. The disagreements may be accounted 

 for by very rapid differentiation, or by modifications or replacements by im- 

 portations. 



The following descriptions are made for most ready comparison with those 

 in the majority of the literature. Percentages are not given as they do not 

 lend themselves readily to visualization, an absolute necessity in descriptions 



