The Shell-bearing Sea Slugs 



Atys Naucum is a pure white bubble-like shell in this 

 family. 



LATHE SHELLS 



Family ToRNATiNiOiE 

 Genus TORNATINA, A. Ads. 



Shell thin, inflated, cylindrical, entirely covering the animal. 

 The spire is concealed, as in Cyprtea. The head and foot are 

 split; the halves are reflected over the shell. The radula is 

 replaced by a powerful gizzard in which molluscan food is ground. 

 So solid and compactly built do these shells seem that to Linnsus 

 they looked as if turned on a lathe, hence the name. 



T. punctistriata, Ads., a minute representative of this 

 genus, occurs from New York to Massachusetts. 



THE BUBBLE SHELLS 



Family Bullid^e 

 Genus BULLA, Linn. 



Shell thin, smooth, ventricose, almost globular; spire pol- 

 ished, deeply pitted; lip plain; body large, fleshy, partially 

 enveloping the shell by reflexing the two wing-like parapodia. 

 Eyes prominent on frontal disc. Quantities of mucus are se- 

 creted by the skin to keep it moist while the tide is out. 



The food of Bulla is molluscan ; the creature burrows in the 

 sandy mud and captures small bivalves and snails which it swal- 

 lows whole and grinds to fragments between the strong walls 

 of the gizzard. The mantle flaps are used in swimming. 



The Cloudy Bubble Shell (B. nebulosa, Gld., B. Gouldiana, 

 Pils.) I have often found on the mud flats of San Pedro, and 

 watched the captive slowly stow away the viscid bulk of its great 

 foot within the ample shell. 1 have washed away the slimy mud, 

 and admired the cloudy splotching of yellow and brown on its 



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