102 



EAST COAST MARINE SHELLS 



on PI. 68. 



Young specimens may be separated 

 from T. acicula by the less convex whorls 

 and weaker ribs. Depth range 7-60 fathoms. 



PI. 33, Fig. 21 



Labrador to Massachusetts Bay 



Family Vermetldae (Worm Shells ) 



Shell often spiral when young, at- 

 tached or free, irregular In adult; aper- 

 ture round; operculum corneous. 



These animals live In sponges, mud, 

 upon shells or coral and are very variable 

 in growth, sculpture, size and color. 



Fig. 43 

 Vermetus nigricana 



GENUS VERMETUS "Adanson" Daudin 1800 



VERMETUS NIGRICANS Dall. Shell brownish 

 violet, irregularly convoluted. 



According to Johnson this is the 

 species forming reefs of the so-called 

 "worm rock." 



Fig. 43 



West coast of Florida to Florida 



Keys 



GENUS SERPULORBIS Sassl 1827 



SERPULORBIS DECUSSATUS Gmelin. Shell rath- 

 er solid; solitary; whorls rounded, longi- 

 tudinally sculptured; decussated by incre- 

 mental lines, color yellowish white, 

 streaked with brown. Depth range 10-22 

 fathoms. 



PI. 46, Fig. 4 



North Carolina to Florida; West 



Indies 



GENUS VERMICULARIA Lamarck 1799 



A thin membranous portion, sur- 

 rounding the operculum, permits the animal 



to close its shell at the aperture and with- 

 draw far inside for safety. 



VERMICULARIA SPIRATA Philippl. Shell chest- 

 nut brown or lighter in color; longitudinal- 

 ly carinated and striated. Length 6-9 

 inches. 



This well-known shell is sometimes 

 a violet-brown. Depth range 0-175 fathoms. 

 The writer found it abundant In shallow wa- 

 ter, with muddy bottom, in Cortez Bay, near 

 Sarasota, Florida. 



PI. 70, Fig. 4 



Vineyard Sound, Massachusetts to 



West Indies and Texas 



Family Caecidae 



Minute shells which develop through 

 three growth stages. In the first the 

 young shell is spiral, this portion being 

 discarded after the formation of the second 

 stage. The second, or adolescent stage, 

 comprises a curved tube which, in turn. Is 

 subsequently lost. In the 

 adult stage the tube is of a 

 similar curved shape and again 

 closed by a septum or plug. 

 Protruding from the latter 

 there is sometimes a mucro, or 

 horn, formed by the apex of 

 the cone. Development of shell 

 is shown in Fig. 44. 



Certain of the species 

 are beautifully sculptured. On 

 account of their small size 

 they are frequently overlooked by collec- 

 tors. A Frenchman, De Folln, specialized 

 on these years ago and many of the species 

 were described by him. 



They often live in large numbers 

 under stones or inside sponges. Once a col- 

 ony is discovered many Individuals may eas- 

 ily be obtained. Fresh dead specimens, be- 

 longing to several species, are often taken 

 in "drift" on the beaches. 



GENUS CAECUM Fleming 1817 



CAECUM PULCHELLUM Stimpson. Adult shell 

 with about twenty-five rounded ribs and 

 somewhat equal spaces between them; plug 

 rounded; operculum concave and with eight 

 whorls; young specimens with few well sepa- 

 rated ribs. Length 2.5 mm. Depth 1-52 

 fathoms. 



PI. 69, Fig. 22 



New Hampshire to the Florida Keys 



Fig. 44 



Development of 



Caecum 



