THE GALAPAGOS TORTOISES. 269 
smoothness: such species are 7’. nigra, T. microphyes, and T. macrophyes. 
Testudo wicina, 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 localities, 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 T'estudo 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 earlier than Van Denburgh’s. Porter’s description of the tortoises 
of Santa Maria (Charles) and Espanola (Hood) applies a little better to 7. 
elephantopus Harlan than to 7. 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 
