The Basket Shells. Dog Whelks 



out. The surface is finely cancellated, and marked with chestnut. 

 The lining is bright orange. It never reaches an inch in length. 



Habitat. — Southern Califorina. 



The Slate Nassa (7\^. tegula, Rve.) is dark gray in colour, with 

 a pale band just below the noduled shoulder of the whorl. The 

 aperture is lined with smooth white enamel. Length, | inch. 



Habitat. — Southern California. 



The Netted Dog Whelk (N. reticulata, Linn.), found on 

 sandy shores from Norway to the Mediterranean, has been the 

 subject of much study. It is an inch or more in length, a robust 

 mollusk in a solid, cancellated shell, brownish white, often banded 

 with chocolate below the suture. Back from its thin edge the 

 lip is thickened and toothed; the columella is smooth with a wide- 

 spread callus. There is considerable variability of sculpture 

 from fine to coarse. 



At the recess of each tide this mollusk buries itself in the sand 

 in a slanting position, its lurking place betrayed by a little hillock. 

 It gets into lobster pots for the sake of the bait. 



Buried in the sand at the bottom of an aquarium, these 

 moUusks will always respond to one stimulus unless it comes just 

 after a hearty meal. Scraps of meat, fresh or stale, make an 

 irresistible appeal. Bones with particles of meat adhering are 

 soon buried by the mollusks. Simply passing a bit of meat over 

 the sand, then withdrawing it, served the same purpose of drawing 

 the animals, so strong is their sense of smell. 



The eggs of this Nassa are laid on seaweed. The capsules 

 are like flat purses, the size of a spangle, on short stems. These 

 are attached to the stems of seaweeds, and overlap each other 

 in a single row. The young escape from the capsule through a 

 hole at the top. They have ciliated lobes by which they swim. 

 The antics they cut are amusing to watch, and seem to be merely 

 playful, but are probably a struggle to resist capture by swarms 

 of infusorians. 



The robust A^. reticulata does great damage in the pares of 

 Arcbachon, where the famous French oysters are raised. Like 

 our destructive "drill," the Nassas of all ages bore the oyster 

 shells, and suck out the soft parts of their helpless victims. The 

 tide sweeps, in bringing fresh thousands of these destroyers, so 

 that combating them is a long, unequal fight. 



Fortunate for our oyster growers the dog whelks of the 



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