62 
THE RACES OF THE GALAPAGOS. 
Tortoises indigenous to the Galapagos archipelago may be recognized by the following 
characters : — The nuchal plate is constantly absent ; the posterior margins of the two 
gular plates are convergent, meeting at a more or less obtuse angle, never forming a 
straight, or nearly straight, transverse line. Neck and legs long. The shell black. 
One of the scutes on the inner side of the elbow is conspicuous for its size, much larger 
than those surrounding it. 
In the skull, the crown is flat ; the palate moderately concave ; the front part of the 
intermaxillary truncated, elevated. The fourth cervical vertebra biconvex. The sym- 
physial bridge between the foramina obturatoria of the pelvis is flat, broader than deep. 
Osseous carapace very thin. Nuchal vertebrae and limb-bones elongate. 
It is evident from this diagnosis that the Galapagos Tortoises are differentiated from 
the Aldabra races by the same important structural characters as those of the Masca- 
renes, to which, on the other hand, they are most closely allied in every respect, except 
in the presence of a double gular plate. The various modifications of the form of the 
carapace and of the sculpture of the scutes which we have noticed in the forms of the 
islands of the Indian Ocean we find repeated in those of the opposite end of the globe. 
Porter's and Darwin's statements that the various islands are inhabited by distinct 
species are fully borne out by my observations. Unfortunately, with the exception of 
the species collected by Commander Cookson, we do not possess positive and exact 
information as regards the localities whence our examples were obtained ; but Porter's 
accounts are sufficiently detailed to enable us to relegate, with more or less certainty, 
some of the species before us to the places of their nativity. James Island yielded 
Tortoises of the broad, circular type ; and therefore either T. elephantopus or T. nigrita 
came from that island, probably the former. There can be no doubt that we have, in 
T. ejjhijjpium, the species inhabiting Charles Island ; T. microjihyes and T. vicina we 
know now to be indigenous to Albemarle, and T. abingdonii to Abingdon Island. Possibly 
other specific forms still exist ; but those of Chatham and Indefatigable (and probably 
Charles) Islands have been extinct for a long time, and not even remains of them are 
known to exist in collections. As has been said in the " Introduction," the fate of all 
