312 Mr. R. M 'Andrew on the Comparative Size of Mollusca. 



Mr. Jeffreys professes to consider seriatim all the instances 

 adduced by me as opposed to his theory, but has omitted to 

 notice the following ten, Pecten Islandicus, Margarita alabas- 

 truniy Astarte arctica, A. incrassata, Fusus antiquus, Triton 

 nodosum, Lucina spinifera, Murex brandarisj Cyprcea lurida, and 

 C. spurca. 



In consequence of Mr. Jeffreys' s remarks (some of which sur- 

 prised me not a little), I have carefully reconsidered the whole 

 of my statement, comparing specimens together where necessary, 

 and now give the result as follows : 



1. Corbula nucleus, from North Drontheim. Mr. Jeffreys's 

 remark would be equally applicable to specimens obtained in the 

 Mediterranean or other southern localities. It is just possible 

 that Mr. Jeffreys may not be aware that North Drontheim is an 

 extensive province of Norway, with a very great range of sea- 

 coast, and that he may have supposed my specimens to have 

 been obtained in one particular locality. 



2. Trochus lineatus. It is probable that Mr. Jeffreys has not 

 seen my specimens from the neighbourhood of Vigo (obtained 

 in 1857 by Mr. Woodward and myself), or he would not have 

 coupled them with those from Mogador. I wish, however, to 

 correct my statement respecting this species, and only to say 

 that the specimens from the neighbourhood mentioned exceed 

 in size the ordinary specimens on the British coasts. 



3. Astarte sulcata I have not found to vary in size more than 

 most other species of Mollusca, much less than its congener 

 A. compressa. I adhere to my statement that it diminishes in 

 size when traced northward from the Scottish coasts to those of 

 Finmark. 



4. Astarte triangularis. Mr. Jeffreys believes that he can 

 match, in point of size, specimens from North Britain with any 

 of mine from Gibraltar Bay, which is of course possible ; but 

 the fact still remains unimpeached that all my specimens from 

 Gibraltar (and they are very few) exceed in size the largest I 

 have obtained in Britain. I have procured it off Scilly, as well 

 as from many localities of Scotland, and at various depths, vary- 

 ing from three to sixty fathoms. 



5. Crenella marmorata. It is possible that Mr. Jeffreys may 

 have been misinformed respecting the large specimens he saw 

 being from Greenland, as I find no mention of it in Moller's or 

 Morenos catalogues of the shells of that country; nor was it 

 among the species dredged there by Mr. Barrett. Indeed it 

 has never been met with, to my knowledge, in the Arctic seas. 



6. Crenella rhombea. The ordinary run of specimens from 

 the Canary Islands is considerably larger than any I have seen 

 obtained in Britain or the Channel Islands. The comparison 



