NATICA. 225 



Var. 2. suhovalis. Smaller, and of a somewhat oval bhape, 

 with a longer spire ; fawncolour or whitish. 



Var. 3. ventricosa. More globose, and short-spired. 



Habitat : Everywhere, in sand^, from the extreme 

 verge of low-w^ater mark to the greatest depth within 

 the line of soundings. Var. 1. W^idely distributed, but 

 not common. Var. 2. Shetland and w^est of Scotland, 

 in deep Avater (J. G. J.); Silverpits on the north-eastern 

 coast of England (Rich). Var. 3. Hebrides (J. G. J.). 

 Fossil in many of our quaternary deposits (Smith and 

 others) ; glacial and post-glacial beds in Norway_, 0-440 

 feet (Sars). Its range, as a recent species, comprises 

 the North Sea from the Loffoden Isles southwards, the 

 western coasts of the North Atlantic, the Adriatic, and 

 both sides of the Mediterranean ; depths recorded from 

 various places 5-80 f. 



It glides swiftly along by means of its broad foot. 

 Mr. Dennis whites me word that it is a very ravenous 

 mollusk, and that, w' hen placed in a basin of sea-water 

 with Scrobicularia alba or other small bivalves, it wall, 

 as soon as night falls, pierce the shells and commence 

 devouring its prey. The spawn-case is not so tough and 

 leathery as that of N. catena ; one now before me mea- 

 sures an inch and a quarter in diameter, the circular 

 hole at the top being half an inch. The pad in very 

 young shells covers about one-half of the umbilicus, 

 a.lthough this latter part is nearly closed in some speci- 

 mens from Shetland. The ground-colour varies from 

 pure white to dark orange; occasionally the spots are 

 confluent, or they are replaced by broad bands, or else 

 by a white zone at the top of each whorl j now and then 

 the upper whorls only are encircled by a single row of 

 spots ; and the streak outside the umbilicus is not unfre- 

 (picntly wanting. Specimens procured by Mr. Jordan 



L 5 



