XVII biSTRIBUTION OF THE SHELLS 417 



from islands in the central parts of the Pacific occurring here, 

 deserves notice, for not one single sea -shell is known to be 

 common to the islands of that ocean and to the west coast of 

 America. The space of open sea running north and south off 

 the west coast separates two quite distinct conchological 

 provinces ; but at the Galapagos Archipelago we have a halting- 

 place, where many new forms have been created, and whither 

 these two great conchological provinces have each sent several 

 colonists. The American province has also sent here representa- 

 tive species ; for there is a Galapageian species of Monoceros, 

 a genus only found on the west coast of America ; and there 

 are Galapageian species of Fissurella and Cancellaria, genera 

 common on the west coast, but not found (as I am informed by 

 Mr. Cuming) in the central islands of the Pacific. On the 

 other hand, there are Galapageian species of Oniscia and Stylifer, 

 genera common to the West Indies and to the Chinese and 

 Indian seas, but not found either on the west coast of America 

 or in the central Pacific. I may here add, that after the com- 

 parison by Messrs. Cuming and Hinds of about 2000 shells 

 from the eastern and western coasts of America, only one single 

 shell was found in common, namely the Purpura patula, which 

 inhabits the West Indies, the coast of Panama, and the Galapagos. 

 We have, therefore, in this quarter of the world, three great 

 conchological sea -provinces, quite distinct, though surprisingly 

 near each other, being separated by long north and south spaces 

 either of land or of open sea. 



I took great pains in collecting the insects, but, excepting 

 Tierra del Fuego, I never saw in this respect so poor a country. 

 Even in the upper and damp region I procured very fev/, 

 excepting some minute Diptera and Hymenoptera, mostly of 

 common mundane forms. As before remarked, the insects, for 

 a tropical region, are of very small size and dull colours. Of 

 beetles I collected twenty-five species (excluding a Dermestes 

 and Corynetes imported wherever a ship touches) ; of these, two 

 belong to the Harpalidae, two to the Hydrophilidae, nine to three 

 families of the Heteromera, and the remaining twelve to as many 

 different families. This circumstance of insects (and I may add 

 plants), where few in number, belonging to many different families, 

 is, I believe, very general. Mr. Waterhouse, who has published ^ 



^ Afin. and Mag. of Nat. Hist. vol. xvi. p. 19. 

 2 E 



