Prof. E. Forbes on the Mollusca of the British Seas. 69 



are not found in any of the volcanic islands of the great 

 oceans. But this idea is not now correct as regards the 

 north island of New Zealand ; though the statement is still 

 apparently correct as regards the other islands in the Pacific 

 Ocean. In the Sandwich group of islands there are neither 

 frogs nor toads.* In the Galapagos Archipelagot there are 

 no frogs or toads, and I have examined men who have lived 

 at Tahiti, the Navigator's Group, the Friendly Islands, Chat- 

 ham Island, Norfolk Island, and many of the other islands 

 in the great ocean which surround New Zealand ; and they 

 all agree that no frogs have ever been found in any of these 

 islands. Perhaps, however, more careful inquiries may de- 

 tect frogs in the hilly rivulets of these countries, as they have 

 been discovered in New Zealand. 



When the character of the now almost extinct native rat 

 in New Zealand became known, it furnished a link in the 

 chain of evidence regarding the countries from whence the 

 New Zealand race originally came ; and the discovery of the 

 frog may throw a ray of light on some obscure geological 

 questions in New Zealand. 



Arthur S. Thomson. 



Auckland, New Zealand, 

 29th November 1852. 



Professor Edward Forbes on the Mollusca of the British 



Seas. 



The mollusca of the British seas are numerous and abun- 

 dant. The varied conformation of the coasts of Great Britain 

 and Ireland, and of the sea-bed surrounding these islands, 

 is peculiarly favourable for the nourishment of a multiplicity 

 of kinds of these animals. The climatal conditions of our 

 area are such as to encourage the presence and perpetua- 

 tion of both northern and southern temperate types, and the 

 influence of very different ancient conditions is manifested 

 by the presence among them of not a few shell-fish of boreal 



* History of the Hawaiian Islands, by James Jackson. Jerves, London, 1843. 

 | Darwin's Voyages; 



