Mr. F. P. Pascoe on some new Longicorns. 119 



C. perversum are likewise larger in the Mediterranean than in 

 our seas. Triton nodosum attains greater size at Malaga than 

 at Vigo or further north, but is smallest in the Azores. Aclis 

 supranitida grows larger at Madeira than in Britain. 



The southern forms of Mollusca appear to follow the same 

 rule as the more northern. Murex brandaris, Cypraea lurida, 

 and C. spurca, not recorded to have been found north of the 

 Mediterranean, attain larger dimensions in the Canary Islands 

 than in that sea. 



There are a few species the larger growth of which appears to 

 be influenced by western longitude or Atlantic exposure. It 

 has been remarked that Tellina balaustina is found larger in the 

 Hebrides and on the west of Ireland than in the Mediterranean, 

 where it is much more frequent. I have obtained it at Gibraltar 

 of intermediate size ; and a valve dredged off Cape Finisterre in 

 Spain was of the same size as the Scottish and Irish specimens. 

 Lucina spinifera is found larger in the Hebrides and west of 

 Ireland than elsewhere; upon the coast of North Drontheim it 

 is quite as small as upon that of Spain. Solen siliqua, Lutraria 

 elliptica, and some other species, are found of extraordinary 

 dimensions in the outer Hebrides ; several others attain larger 

 growth in Bantry Bay than on any part of the English coast. 



From the examples I have stated (and there would be no dif- 

 ficulty in adducing more of a similar character) I think we may 

 fairly come to the conclusion, that, although there are exceptions 

 in both directions, and although the size attained by Mollusca 

 may be influenced by various conditions in different localities, 

 as a general rule, each species attains its greatest size, as well as 

 greatest number, in the latitude best suited to its general deve- 

 lopment ; and that, whether a species be Arctic, Boreal, Celtic, 

 or Lusitanian, it will grow largest in the region to which it 

 belongs. 



XII. On some new Longicornia from the Moluccas. 

 By FRANCIS P. PASCOE, F.L.S. &c. 



IN Mr. Wallace's last collection from Batchian, in the Moluccas, 

 there are about one hundred and fifty Longicorns, mostly new 

 to science, but referable (with two or three exceptions) to genera 

 which appear to be more or less frequent in the Indian Islands. 

 The new forms, one of which resembles the South American 

 genus Onychocerus in habit, and of which a second species is 

 found in New Guinea (Aru), are confined to Mr. Wallace's pri- 

 vate collection, and therefore, unfortunately, cannot now be 

 described; but amongst the others there are a few species which 

 are interesting either as indicating a more extended range of the 



