THE GALAPAGOS TORTOISES. 293 
scute back and downward to the lower edge of the supracaudal, which last 
extends back about as far as the marginal at each side of it. In the forward 
half of the body the back retains its height, even rises in males or some old 
females, or curves down toward the nuchal notch in most females and the 
young. Across the first pair of costal scutes the body is compressed into a 
blunt angle with its apex in the foremost vertebral; from this scale a groove 
descends along the hinder edges of the reverted marginals of the foremost three 
pairs and ends at or in the fourth marginal at each side. In front the opening 
into the carapace is nearly two thirds as high as it is wide, narrowing upward. 
The marginals form scallops along the edges. Similar to that at the fourth 
there is another indentation in the eighth marginal of each side, from which on 
the upper sides each of the posterior three pairs of marginals forms a groove 
to the caudal scale, by the recurvature of the scales. The concentric striae are 
present except on some old individuals; the areolar spaces are moderately 
larger and more or less convex and prominent; they are smooth except perhaps 
on scales of the very young. 
On the sternum the gulars are broad, about five sevenths of the width of 
the anals; they are rounded in front and have a slight notch between them. 
The outer edges of the humerals are concave, in large specimens; they are 
longer than the femoral scutes. The pectorals are short, but meet on the median 
line. The anal extremity of the sternum is short, broad and subtruncate behind. 
The anal scutes are broader than long, are thickened and swollen downward, 
and are partly separated by a notch below, much like that on specimens of 
T. vicina. The sternum is concave from the anals to the gulars; the concavity 
is greatest from the femorals through the hinder halves of the abdominals, 
farther forward it becomes shallow and disappears; it is less marked in females 
and is absent in young. The specimen to which particular reference is made, 
Plate 41, was secured by Dr. Baur on Pinzon (Duncan) Island. The lateral 
ridges on the marginals of the flank are low; they become weaker with age. 
Females of twenty-one inches from the same island are higher and more 
arched on the back, less broadened posteriorly, more declivous in the first 
vertebral shield and are less concave in the sternum. With age the length 
becomes greater as compared with the width; this with the worn and broken 
scales of the second and the third pairs of the anterior marginals induces indi- 
vidual differences which might lead to selection as types of new species. The 
color of 7. elephantopus in general is a black or blackish brown, marked with 
yellow in places on the lower surface. This species, including its varieties, is 
one of the most distinct of the Galapagos tortoises. The variations of indi- 
