THE DOG- WHELK. 13 



so strong and so elegant a dwelling. For the present, 

 however, as the month is January, we shall, if we sit 

 still longer, run the risk of " catching a cold," if we 

 catch nothing else, though the wind is in the south, 

 and the temperature is so mild for the season. 



Therefore, we will move about and pursue our re- 

 searches among the rocks and under the loose stones. 

 Well, we are rewarded with other specimens : here are 

 several neat little shells, with a lengthened spire, and 

 with a remarkably thickened lip. This is the little 

 Thick -lipped Dog -whelk, 1 a very common mollusk 

 with us under such stones as these at low water-mark. 

 And here is another species of the same genus, the 

 Netted Dog- whelk, 2 which is a much larger shell, being 

 nearly twice as long as the former, and marked with 

 close transverse furrows, which, crossing the longitu- 

 dinal ribs at right angles, give a peculiar reticulate 

 surface, on which the specific name is founded. 



Comparing these shells with the Trockus, we see that 

 they have a deep notch cut in the front part, of which 

 no sign appears in the latter ; and this mark, trivial as 

 it may seem, is an important indication of the habits of 

 the animal. The inhabitants of all shells which have 



1 Jfassa incrassata. 



" Nassa reticulata. A figure of this species is seen in the lower left 

 corner of Plate I. 



