GALAPAGOS TORTOISES 
305 
Tres Marias, Galapagos and Chiloe islands. Beyond this 
centre of distribution there are only two remote stations, one 
in Madagascar, the other on the Fiji islands. We could not 
have a better example of discontinuous distribution, which, 
as Dr. Wallace has always urged, is a proof of antiquity. 
Lastly, the Galapagos snake belongs to the ancient family 
Colubridae, which also includes Tropidonotus, a genus 
specially alluded to (pp. 128 and 222). 
In spite of these facts, Mr. Heller * expresses the opinion 
that the archipelago is mostly of Tertiary age, and that the 
fauna has been chiefly derived from material carried by ocean 
currents. 
Still another expedition has lately been sent to the archi¬ 
pelago by the California Academy of Sciences. Dr. Van 
Denburghf who was asked to report on the reptiles feels quite 
convinced that the islands must all at some former period 
have formed parts of a single land-mass. In a letter which he 
addressed to me, he implies that several species of snakes 
inhabit the islands. He states that “the closest relatives 
of the serpents of the Galapagos archipelago are native to the 
Bahamas, Greater and Lesser Antilles, Costa Bica and the 
whole of South America. This being true, the snakes of these 
localities must have had a common origin. Either the West 
Indian and Galapagos snakes have been derived from South 
America, or else all must be descendants of species occupy¬ 
ing a great central land-mass which has sunk below the level 
of the sea, leaving mere remnants in Central America, 
northern South America, the Antilles and the Galapagos. 
Either view implies a former land connection and a con¬ 
tinental origin of the Galapagos ophidian fauna. 1 cannot 
bring myself to share the opinion of those who believe that 
the fauna of the Galapagos has reached these islands by the 
more or less accidental agency of the winds and ocean 
currents.” 
When Dr. Stearns J reported upon the land and fresh-water 
snails inhabiting the Galapagos archipelago, he alluded to one 
* Heller, E., “ Hopkins-Stanford Expedition : Reptiles,” pp. 46—48. 
t Denburgh, John Van, “ Preliminary Descriptions of Land-tortoises,” 
p. 1. 
J Stearns, R. E. C., “ Mollusk-fauna of the Galapagos,” pp. 359—370. 
L.4. X 
