THE GALAPAGOS TORTOISES. 27.-, 



1875, Plate 3 5 A, from a thirty-three inch specimen, are included in Plate 7. 

 Specimens at hand are more curved from the middle of the fourth vertebral 

 scale to the anterior marginals than in this drawing. In the fourth vertebral 

 and backward the curve is sharp, but the marginals are less declivous, which is 

 also true of the forward marginals. On both front and back the marginals are 

 somewhat reverted, concave on their upper surfaces, in the older specimens. 

 A number of the specimens in the M. C. Z. were secured by Webster near Iguana 

 Cove in the southern part of Santa Isabela (Albemarle); these are compared 

 with the figures of those secured by Van Denburgh in the same locality. The 

 declivity from the middle of the fourth vertebral backward is usually greater 

 than that forward from the second. The caudal plate is directed downward, 

 and slightly forward at the lower edge. A large shallow notch partly separates 

 the marginals of the foremost pair. The indentation at the fourth, and that 

 at the eighth marginal, on each side are shallow, as also the grooves, compres- 

 sions, extending from them. Except perhaps on specimens of greater age, 

 the concentric striae are present. The areolar spaces vary in convexity; in 

 cases they are prominent. The carapace is broader posteriorly; it appears 

 subtruncate, the caudal scale being indented between the marginals at each 

 side of it. In front the margin is the more rounded, subacuminate. Above 

 the humeral and the femoral arches the marginals form scallops. 



The sternum of the type is longer than broad; the humeral extension, 

 in front of the bridge, is broad at the end and is somewhat concave on its lateral 

 margins in the large specimens. The femoral extremity is shorter, broader, 

 and is convex on the lateral margins of the abdominal plates. In both young 

 and old the gulars thicken upward; on the aged they have a comparatively 

 small amount of the downward swelling. The anal scutes are broader than the 

 gulars and have an angular notch between them ; they thicken and curve down- 

 ward with age. The sternal concavity is deepest below the hinder portions of 

 the abdominal scales; it is deeper on the old males. 



In recent collections of specimens of this species there are appearances of 

 considerable mixtures by transportation from one island to another. The 

 earlier captures appear more distinct than some of the later ones. Undoubt- 

 edly the oil collectors, the orchilla pickers, the meat hunters and others were 

 quite ready to contribute to a distribution that has left traces in various direc- 

 tions, and latterly the young specimens from different islands have been on 

 sale within reach of collectors at particular localities. 



