EAST 90 AST MARINE SHELLS 



117 



sixteen varices which are arched like tiles; 

 faint revolving sculpture on adult speci- 

 mens. 



This the largest American Trophon 

 sometimes attains a length of 53 mm. It is 

 chiefly obtained from haddock stomachs. 



PI. 42, Fig. 16 



Iceland to Labrador; Newfoundland 



Banks to Massachusetts Bay 



TROPHON TRUNCATUS Strom. Whorls six; num- 

 erous low, close-set varices which are 

 often obscurely crenulate; suture well im- 

 pressed; canal short and obliquely trun- 

 cate; aperture and canal shorter than spire. 

 Length 12-17 mm. Depth range 10-50 fathoms. 



The most common North Atlantic 

 Trophon. 



PI. 44, Fig. 13 



Flnmark to Greenland and south to 



Georges Bank 



Family Thaisidae 



Shell striated, imbricated or tuber- 

 culated; spire short; aperture usually 

 small. Animal similar to Murex. 



Many of these mollusks produce a 

 fluid which creates a crimson dye. This 

 may be observed by exerting pressure upon 

 the operculum. They are largely predatory 

 and in Europe are destructive to the mussel 

 beds. 



GENUS THAIS Roeding 1798; Purpura 

 Bruguiere 1789, not Martyn 



SUBGENUS PATELLIPURPURA Dall 1918 



THAIS PATULA Linne. This species develops 

 a capacious aperture and numerous nodules 

 upon the back of the shell. These knobs 

 are less distinct in mature specimens. The 

 outer lip has sharp teeth inside the edge, 

 the base being hardly notched. The color 

 is dark brown, interior often bluish. 

 Length 1-3 inches. 



A widely distributed species which 

 varies considerably In size. 



PI. 45, Fig. 8 



Jupiter Inlet, Florida to Brazil; 



Pacific 



SUBGENUS STRAMONITA Schumacher 1817 



THAIS FLORIDANA Conrad. With or without 

 two rows of low tubercles; sculpture strong; 



color whitish, blotched and streaked with 

 brown. The interior is often pale brown 

 with a white border inside lip. Length 1-2 

 inches. 



This shell is common upon rocks al- 

 most everywhere in Florida and along the 

 gulf coast. The radula is shown on Plate 

 64. 



PI. 45, Fig. 9 



PI. 48, Fig. 3 



PI. 64, Figs. 3, 4 



North Carolina to Texas; West 



Indies 



THAIS FLORIDANA HAYSAE Clench, Shell large, 

 dull gray or brownish gray, whorls six to 

 seven; two rows of large tubercles on each 

 whorl slightly above center, these in turn 

 two to three ridged, becoming two ridged at 

 base; spire acute and produced; inner mar- 

 gin of lip crenulate; pinkish or orange in- 

 side; suture deep. Length 3.5 inches. 



PI. 45, Fig. 13 



Grand Bayou, Mississippi Delta', 



Louisiana 



THAIS DELTOIDEA Lamarck. Principal rows of 

 nodules placed above periphery, bluntly 

 pointed and indistinct row below; parietal 

 callus broad, pink color and blotched with 

 brown; blotches sometimes upon lip which is 

 slightly crenulated; axis slightly twisted 

 to form a short canal. Length 1 inch. 



A chunky form, usually well covered 

 with incrustations and therefore not readi- 

 ly detected upon coral rocks. 



PI. 44, Fig. 10 



Jupiter Inlet, East Florida to St. 



Vincent, West Indies 



SUBGENUS NUCELLA Roeding 1789 



THAIS LAPILLUS Linne. An excessively vari- 

 able shell, both in form and color. It is 

 very largely influenced by environment. 

 Very thick heavy, specimens are found in ex- 

 posed situations on the coast of Maine. 



The shell is generally pointed at 

 both ends. It is variegated with yellow, 

 brown and white. Upon the surface are 

 coarse revolving ridges. The aperture is 

 thickened and has teeth inside. It lives 

 on ocean rocks everywhere within its range 

 and is also common in northern Europe. 

 Length 1-1.75 inches. 



The ovicapsules are shown on PI. 69, 

 Fig. 3. 



