RANDOM NOTES ON NATURAL HISTORY. 



The Shell - Bearing Mollusca of Rhode 

 Island. 



[BY HORACE F. CARPENTER.] 



Chapter VI. 

 4. Purpura (Polytropa) lapillus, Linn- 

 Syns. : 



Biiccinum lapillns, Linn. Penn. Wood. 

 Don. Mont, etc. 



Tritoniuni lapillus, Muller. 



Purpuio-biiccinuni, Da Costa. 



Purpura lapillus, Lam. Kiener. Gld. 

 DoKay. Stimp., etc. 



Shell ovate, acuteh' pointed at both ends, 

 thick and solid, with almost evei-y variety 

 of coloring, from pure white, through yellow 

 to dark brown,somc with bands of white, yel- 

 low or red, of various widths. The shape of 

 the shell and its surface is also much varied, 

 as are nearly all littoral shells ; some speci- 

 mens being perfectly smooth, and others 

 very rough to the touch ; some have raised, 

 acute, turreted spires,, while others are 

 flattened below the suture. The aperture 

 is oval, the outer lip curved and sharp, but 

 thickened and armed within with blunt teeth ; 

 inner lip smooth and somewhat flattened. 

 Length, one and one-fourth inches. Breadth, 

 seven-tenths. These shells are not found in 

 our bay, but inhabit the ocean rocks at 

 Newport, and are common on both sides of 

 the Atlantic, extending northwards to the 

 Arctic seas. The geographical centre of 

 this species is in northern Europe, the 

 American as well as the southern European 

 and African specimens being stunted in 

 size. Its fossil distribution extends as far 

 back as the Red Crag of England. It is 

 carnivorous in its habits, feeding upon dead 

 fish, mussels, and bivalve shells generally. 

 It is especially fond of oysters, and is con- 

 sidered a very destructive enemy to the 

 oyster-beds in England. 



Most of the Purpurae contain a liquid 

 which produces a crimson dye, obtained by 

 pressing on the operculum or by crushing 

 the shell. The celebrated Tyrian dye of the 

 ancients is supposed to have been made 

 from these animals. When this liquid is ap- 

 plied to linen and dried in the sun, it first 

 appears of a light green color which changes 

 to a deep green, then into blue, and then to 



a deep purple red ; if now the linen be 

 washed in hot water and soap and again 

 dried in the sun, it becomes of a beautiful 

 bright crimson, which is indelible, and 

 without the use of any other reagent to 

 set it. 



Family 2. Tkitonid^, containing four 

 fossil genera and three recent genera and 

 eight sub-genera, with one hundred and 

 three fossil and one hundred and forty-four 

 recent species^ is not represented at all in 

 New England. 



Family 3. Fusid^, comprising four sub- 

 families, ten genera, seventeen sub-genera, 

 three hundred and thirty fossil and one 

 hundred and sixty recent species, is not 

 represented in Rhode Island. One species 

 only, Ptychatractus ligatus, Migh and 

 Adams, is found on the coasts of Maine 

 and northwards, in deep water. 



Family 4. Buccinid.<e, is divided into 

 six sub-families, twenty-six genera, with six 

 sub-genera and hundreds of species, both 

 recent and fossil. This immense family' is 

 represented in Rhode Island by three genera 

 and five species, as follows : 



Sub-Family, Neptuniin^. 

 Genus, Sipho, Klein. 



Shell thin, pyriform or fusiform, not tuber- 

 culate or spiny, smooth and rounded whorls ; 

 spire moderate ; canal produced and re- 

 curved. Operculum ovate, nucleus apical. 



5. Sipho Stimpsoni, Morch. 



Dist. Long Island to Labrador. Deep 

 water. This shell has until recently been 

 confounded with Sipho Islandicus, which is 

 a northern shell, inhabiting Iceland, and 

 Greenland to Labador, and Norway to 

 Scotland. It is more ventricose than that 

 shell, with a shorter, wider and more curved 

 canal. A robust shell, with a dark, rough 

 epidermis. Length, two and one-quarter 

 inches, breadth about one inch. 



6. Sipho ptgm^us, Gould. 



Shell white, under a yellowish epidermis : 

 whorls six, and preserving the same out- 

 lines as the previous species. The compar- 

 ative length of the aperture is less, and the 

 striae are more numerous and more rounded, 



