The Basket Shells. Dog Whelks 



paler band around the body whorl. The surface is spirally 

 grooved, but faintly so, and crossed by lines of growth. The old 

 shells are dilapidated affairs, with a sort of marine mould grown 

 thick upon them, like an epidermis. The aperture is dark 

 brown with white banding; the lip simple, a callus covering the 

 columella. 



The body is grayish and mottled, with the power to extend 

 far out of the shell. Shell and body are well protected, for they 

 are dingy, like the muddy sand in which they live. The latticed 

 surface catches the sand, so that an exposed shell is hard to dis- 

 cern until it moves. 



This Nassa lays its numerous egg-capsules in spring on the 

 lining of the egg-collar of Natica, or on a dead clam shell, crowding 

 them always close together. Each is an elaborately spiny, trans- 

 parent object on a short stalk. 



No mollusk of equal size is more in evidence on the Atlantic 

 coast. Especially does it throng the muddy shores where by 

 the emptying of streams the water is somewhat brackish. On 

 mud flats, exposed at low tide, they may be seen by thousands, 

 scrambling nimbly about doing scavenger duty. A dead crab 

 or fish calls together an army of them, which soon dispatch the 

 ill-smelling object. Obliged to find live prey, they bore the shells 

 of bivalves, and are even suspected of eating each other at a 

 pinch. The largest is an inch long. 



Habitat. — Nova Scotia to Florida. 



The Lash Nassa (N. vibex, Say) is the handsomest of the 

 basket shells. Strong longitudinal ridges, set far apart, cross the 

 fine spiral ones, forming nodules at the shoulder of each whorl. The 

 shell is heavy; the toothed lip thick; the callus of the columella 

 spreads out into a broad flat triangular patch on the body whorl. 

 The colouring is chestnut and white, in bands and clouds. 

 Length, f inch. 



Habitat. — ^West Indies, to Chesapeake Bay and Cape Cod. 



The Lean Nassa (A^. mendica, Gld.) has a slender, strongly 

 sculptured shell, of fine revolving lines crossed by remote, promi- 

 nent ridges, broken by the sutures. The exterior is marked with 

 pale brown ; the interior is white. Length, i to f inch. 



Habitat. — Puget Sound to San Diego, Cal. 



The Fat Nassa {N. perpinguis, Hinds) resembles N. fossata 

 in its stout figure, and in other particulars, but it is smaller through- 



73 



