326 MOLLUSCA.—RADIATA. 
the coasts of Cornwall in October after it had 
quitted us ; but again in 1838 great numbers ap- 
peared on the same coasts in March and afterwards 
in July, before coming to usin Devon. These facts 
added to others continually heard of or read in 
newspapers, shewing the irregular or uncertain 
appearance of this fish on the coasts it frequents, 
strongly announces the incorrectness of the idea of 
its multiplying within the Arctic circle and passing 
bodily at a certain time from thence to the tempe- 
rate regions. 
Our subject gradually loses interest as we descend 
to the lower tribes. Of the Mollusca we possess a 
considerable number. ‘They seem to predominate 
however in those portions of the class which cha- 
racterize bold rocky shores, and possibly the same 
remark holds good relatively to other tribes of 
marine animals. It is likely that this will account 
for the same animal being frequently found on shores 
of the same character, though far distant. Thus, 
we very often meet with shells stated to have been 
taken on the coasts of Devon and of Shetland, so that 
although the geography of shells is so very intricate 
it may yet be detected that situation has much 
control over it. More than 300 marine molluscs 
have been recognised with us. 
Since the time of Montagu but little has been 
done in illustration of the remaining marine tribes 
of Devon, the Radiata, of which however at the 
present time we can boast of nearly 120 species 
found on the Devon shores, and I have certainly 
no doubt that this number might be greatly in- 
creased by diligent and keen research. The sponges 
of our coast in particular require illustration, and 
I am of opinion that not more than three-fourths 
of them have been named. We see frequent in- 
stances among the lower tribes, of species peculiar 
to the southern shores of England representing by 
