SEA-SNAILS AND SEA-SLUGS. 



213 



one Star-fish eating or digesting three Purples at once. It is 

 a case of " diamond cut diamond," for you would think a 

 Mussel or a Limpet would be safe enough with the shell 

 closed down, and so you might suppose the Purple's operculum 

 would shield him from the Star-fish ; but as I have already 

 described in an earlier chapter, the Star-fish knows well how 

 to deal with obstinate victims who won't show their noses out- 

 side the door when their enemy calls he digests them first, and 

 swallows them afterwards. Here is a complete reversal of the 

 Shakespearean motto, " May good digestion wait on appetite; " 

 to be complimentary to the Star-fish we should say, " May 

 appetite on good digestion wait ! " In the bottom left-hand 

 corner of the purple-and-limpet illustration, is a baker's dozen 

 of nine-pins : they are the egg-cases of the Purple, which may 

 be found in larger or smaller patches on any rock where these 

 mollusks abound. 



Among the weeds on 

 the rocks we are sure to 

 find the Netted Dog- 

 whelk (Nassa reticulata), 

 with a rather dirty-look- 

 ing shell. It is covered 

 with broad grooves cros- 

 sed by fine lines at 

 right angles, producing 

 the appearance of net- 

 work, which gives it the 

 distinctive name, netted. 

 Its scientific name also is 

 suggested by the same 

 appearance, for Nassa is Latin for a special kind of fishing-net. 

 Like the Purple, the Dog-whelk is carnivorous. There is a 

 prettier species, with a thick lip, called Nassa incrassata. 



The true Whelk (Buccinum undatuni) only comes within 

 our province in the shape of empty shells cast up on the 



NETTED DOG-WHELK. 



