152 New York State Museum 



fast by a stony cement secreted by the foot. The shell 

 is decidedly convex and of a gray, horny color with 

 faint reddish brown flecks over the surface. The 

 shape and the shelly partition inside give these shells 

 their popular name. The Sand Flat Snail {Nassa tri- 

 vittata) is also found on muddy and stony bottoms, 

 extending into water about 240 feet deep. It ranges 

 from Florida to Nova Scotia, and is most abundant 

 on the Massachusetts coast north of Cape Cod and 

 on the sand flats of Long Island sound. It is a small 

 shell, five-eighths of an inch long, and is carnivorous, 

 boring through the shells of other mollusks. It re- 

 sembles the Mud Flat Snail, but may be distinguished 

 by the sharp spire and regular granular surface. There 

 are many other snail shells to be found on our sandy 

 beaches, but those mentioned above are found most 

 commonly. One of the most graceful and one of the 

 larger shells of our eastern coast, a deepwater dweller 

 occasionally washed up on the beach, is Stimpson's 

 Sipho (Sipho stimpsoni). This form is almost identi- 

 cal with one of North European waters and for a long 

 time was thought to be the same species. It is not 

 found south of Cape Cod and ranges north to New- 

 foundland, living in waters 20 to 100 feet deep. The 

 shell is three to five inches long, with a high spire 

 and seven to eight whorls with simple sutures. The 

 epidermis is thick, horn colored and sometimes vel- 

 vety, but the shell beneath is pure white. There are 

 four or five exceedingly common species of Ladder 

 Shells and Wentletops (Scala), all found on the beach 

 after a storm or they may be dredged in shallow water 

 near the shore. One species ranges from Cape Cod 

 to Florida ; some from Cape Hatteras to New England 



