448 Mr. J. Gwyn Jeffreys on Dredging-Reports. 
LX.—Reports on Dredging. By J. Gwyn JEFFREYS, F'.R.S. 
I HAVE not much to say in answer to the remarks made by 
Mr. M‘Andrew in the last Number of the ‘ Annals,’ because 
it seems to me that we do not differ in any very material 
point. 
With regard to “ bathymetrical” zones (in which, of course, 
I did not mean to include that part of the shore which lies 
“beyond the reach of ordinary tides’’), I am satisfied with 
my friend’s admission that “the same species often frequent 
different depths in different seas :”’ from my own experience in 
dredging (now of between thirty and forty years), 1 would say 
the same seas. I am not a disbeliever in zones, having, in my 
work on ‘ British Conchology,’ adopted and endeavoured to 
define four,—viz. littoral, laminarian, coralline, and deep- 
sea; but the first two and last two of these constitute two 
principal zones, which may be termed littoral and submarine. 
Some species of Mollusca, as well as of other animals, range 
from low-water mark to the greatest depth reached by the 
dredge. 
The question as to the comparative size of northern and 
southern specimens of the same species was so fully discussed 
by us in the ‘ Annals’ for 1860, that it is unnecessary to con- 
tinue the controversy. I would, however, observe that perhaps 
our disagreement on this point may in some measure arise 
from my considering certain forms mere varieties which other 
conchologists hold to be distinct species. I have elsewhere 
given my reasons for uniting Pecten septemradiatus with P. 
clavatus, Lima hians with L. tenera, and Astarte sulcata with 
A. elliptica and A. fusca or incrassata. 'The last named in 
each case I regard as the southern form, and the others as the 
northern form of those three species. Mr. M‘Andrew did not 
find Pecten septemradiatus on the Scandinavian coast so large 
as those of Loch Fyne. A valve from the Faroe banks, 
dredged by Dr. Carpenter and Professor Wyville Thomson, 
measures an inch and nine-tenths in length; this far exceeds 
any I have seen from Loch Fyne, where the species is com- 
mon. He also says that his specimens of Astarte sulcata from 
Gibraltar and from Finmark are equal in size; and he agrees 
with me that size diminishes with depth. His dredging-lists 
record that species from 45 fathoms at Gibraltar and 15-160 
fathoms on the western coast of Norway. Possibly his Fin- 
mark specimens came from the deepest water, and were con- 
sequently smaller than those from Gibraltar. But even if it 
were not so, my proposition was qualified; and every rule has 
its exception. 
