22 CALIFORNIA SEA SHELLS. 



plates which overlap like shingles. The surface 

 is rough and deeply sculptured. The aperture 

 is oval, with thin, projecting lips, which make, 

 by a fold, a prominent horn near its base. The 

 sfphonal canal is long, closed, and curved at the 

 tip. The outside of the shell is of a dull white, and 

 the inside is lined with a beautiful white enamel. 

 The operculum looks like a thin chip of rose 

 wood. 



Cerostoma Nuttallii, Conr. Fig. 1, PL IV, Nut- 

 tail's FTornmouth, resembles the last but is small- 

 the varices are not so broad and thin, while the 

 spaces between them are tubercled and marked 

 with but little spiral sculptuing. It was named 

 for the eminent naturlist, Xuttall. 



The genus JVassa, which we will next con- 

 sider, has several representatives on the coast of 

 California. The name means " a basket for 

 taking fish," and refers to the netted surface of 

 most of the species. Among our most common 

 species we mention JYassa fossata, Gld., Basket 

 Shell, shown in Fig. 2, PI. IV. It is the largest 

 of our species. Spire, conical, consisting of live 

 or six whorls ; surface, sculptured by spiral and 

 transverse grooves. The inside of the outer lip 

 is also grooved, and the aperture ends in a short, 

 strongly reflexed canal, through which the 

 animal sends up its nose-pipe, when it is search- 

 ing the sand for bivalves. [Near the base of the 

 body whorl is a deep spiral ditch, or " fossa," 

 which gives a name to the species. Color, yellow- 

 ish white, deepening in the mouth to a brown- 

 ish orange. Length, from one to two inches. 



Nassa perpinguis, lids., Fig. 3, PI. IV, resem- 



