^L. pica.^ This large and interesting trochid is a West Indian species which sometimes occurs in Florida. It lives about coral reefs and rocky shores, attaching itself in vast numbers to the rocks. This shell is a favorite refuge for large hermit-crabs. It is a curious sight in certain of the West India islands to see a /Livona pica/ shell scrambling up a tree, looking very much out of place upon the back of some terrestrially inclined crustacean. When well cleaned it is a beautiful shell, with black wavy lines over a greenish-white nacreous foundation. The animal has a row of waving cirri upon each side of the mantle, and long, slender tentacles. It is largely used as an article of diet in the West Indies and Central America. (Plate LXVII.) FAMILY ~TURBINIDÆ~ This family is very closely allied to the trochids, the most striking difference being in the operculum, which in the /Turbinidæ/ is calcareous and usually smooth and very convex on the outside. [pg363] The shells are nacreous within, and the animal, with its rows of waving cirri upon each side, is very suggestive of /Trochus/. They are, for the most part, shallow-water or littoral forms. [Illustration: PLATE LXVI. 1, Lucapina crenulata. 3, Chlorostoma brunneum. 2, Haliotis splendens. 4, Neritina reclivata, enlarged. 5, Trochiscus norrisi.] [Illustration: PLATE LXVII. Livona pica, reduced. Turbo castaneus, enlarged. Nerita peleronta. Chlorostoma funebrale. Nerita tessellata.] GENUS ^Turbo^ ^T. castaneus.^ This species has a range as far north as Cape Hatteras, and is especially abundant at Tampa, on the west coast of Florida. The peculiar operculum is sufficient to identify the genus at once. One variety of this species has a crenulated shoulder upon the body-whorl and is referred to as ^Turbo crenulatus^, A series of intermediate forms establishes the specific identity of the two varieties. (Plate LXVII.) FAMILY ~NERITIDÆ~ The /Neritidæ/ are strictly littoral forms, almost entirely confined to the warmer waters of tropical seas. The animal preserves the usual diatocardian features—has a short snout and long tentacles. Unlike the trochids and /Turbo/, it has no cirri along the epipodial margin. The shells are peculiarly shaped, the spire being greatly flattened and scarcely noticeable on account of the unduly large development of the body-whorl; thus the shell takes on a decidedly patelliform appearance. It is without an umbilicus. In the principal genus /Nerita/ the outer lip is sharp on the edge, but greatly thickened just within. GENUS ^Nerita^ ^N. peleronta.^ This shell has two teeth on the wide, flat columellar lip, and about them is a blotch of red, suggesting blood. The common name of this shell, "bleeding-tooth," is very appropriate. Found in southern Florida. (Plate LXVII.)