PREFACE. vii 



Coral Islands, consists in the preponderance of the Gecko and Scink 

 families, to the exclusion almost of all other Saurians, save a genus of 

 lyucutidae, more intimately related to the species of the same family 

 indigenous to the New World, than to those of the Old, should the 

 dentition establish primary relationships ; we allude to the genus 

 Brachyloplim. Amongst Snakes, the aquatic tribes only were noticed, 

 with the exception of a Boa, of a peculiar genus (Enygrus). As to 

 the Tortoises or Sea Turtles, found about those islands, they have 

 proved, contrary to all expectation, characteristic species of the Poly- 

 nesian Fauna, as much so as any of the other reptiles. 



An interesting result, touching the geographical distribution of the 

 species of the genus Proctotretus, has been deduced from a comparative 

 study of the specimens collected on the coasts of Patagonia and Chili. 

 Hitherto, several of the species alluded to stood on record as inhabit- 

 ing simultaneously both these remote localities, although it was con- 

 ceded that " these facts, interesting as they were, had never been 

 sufficiently investigated,"* and were put down as anomalies in the laws 

 of geographical distribution of animal life, laws otherwise so precise. 

 Now, as far as the species of the genus Proctotretus are concerned, 

 those anomalies no longer exist : the species of the eastern coast of 

 South America having been found specifically distinct from those of 

 the western coast of the same continent. As regards Bufo cliilensis, 

 alluded to by Thomas Bell, no opportunity was afforded us to investi- 

 gate the subject. 



C. G. 



* The Zoology of the Voyage of H. M. S. Beagle, under the command of Captain 

 Fitzroy, K. N., during the years 1832 to 1830. Part. V, Reptiles. London, 1843. 



