of this species and Natica hews and they all vary in their outlines. 

 Living almost completely immersed in the sand they plough ahead 

 leaving a long, sinuous track on the beach. The individual shows no 

 timidity and if one places his finger in the track of the animal the 

 creature pushes strongly against it; accustomed as it is to push against 

 pebbles and other objects buried in the sand it does this without 

 alarm. The creature is very sluggish in its movements and three 

 hours were consumed in attaining full expansion. The anterior por- 

 tion of the foot formed a broad, sloping shield, in color and wrinkles 

 closely resembling the pileus of the common edible mushroom. The 

 creature is yellowish fawn, the propodium darker and the outside edge 

 very dark colored. The tentacles are widely separated, short, broad, 

 at base, flattened and curved outward, they are usually closely 

 appressed against the shell and partially concealed by the propodium, 

 as in all Naticas thus far examined; rarely are the tentacles seen free. 

 The curious fold of the foot on the left side as seen in Natica heros was 

 not seen in Natica duplicata. This fold represents a rudimentary 

 syphon. 



BELA DECUSSATA Couthouy 

 PI. IV. Fig. 29. Length 10 mm. 



The animal is nearly transparent with minute white dots marking 

 its surface. The foot is long, narrow, truncate in front, its anterior 

 margin finely wrinkled; tentacles capable of considerable expansion, 

 wide apart; eyes third way down from tip of tentacles. Jeffreys' 

 figure of this species shows shorter tentacles with eyes half way up. 

 He says "American specimens are much smaller than ours as is also 

 the case with Purpura lapillus and Buccinum undatum." 



COLUMBELLA LUNATA Say 



PI. V. Fig. 30. Length 5 mm. 



Foot long, narrow, tapering behind; tentacles short, blunt, 

 thickened, meeting at their bases, eyes at thickened base. Foot pro- 



16 



