488 & MAZATLAN UNIVALVES 
is however by no means constant in colour and markings ; nor 
are the Atlantic shells more so. One perfect adult specimen 
was found, with 12 whirls, one young with 8, and one adult 
partially decollated with 6; else all the specimens were broadly 
truncated, leaving only 4, in the young occasionally 3 whirls. 
The early whirls are glossy and colourless ; apex slightly 
flattened. The ground colour is either dark or very light 
purplish brown, with infrasutural spots distinct; and either 
large or very small, regular or irregular, spots of very pale 
colour over the body. Colour generally darker round the peri- 
phery. Epidermis very thin, of alight greenish horn colour. 
Base with spiral strie. Labrum with 9-12 teeth, of which 
that next the shoulder is elongate. Labium broad, smooth. 
The operculum is very long, and thin, large for the shell, 
horny, with faint ridges of growth. The perfect specimen 
measures long. 55, long. spir. °34, lat. ‘19, div. 28°. 
An ordinary sp. oA: hy DO un Doe Mao Ne 
Hab.—Java Seas, VM. Leschenault, Lamarck.—Ascension Isl. 
Quoy & Gaimard.—Corea, Kiener.—Guinea, Tams.—Cuba, 
Sagra.—Barbadoes, Cutting —Panama, under stones, very 
common, Cuming.—Taboga and Panama; under stones not 
far above low water mark, not common, C. B. Adams.— 
Mazatlan; Col. Jewett.—Do. rare; L’pool Col. 
Tablet 2304 contains a small white shell with 5 whirls, which 
may possibly be the young of this species. It was found in 
the mouth of a Trivia sanguinea. 
Tablet 2305 contains the perfect adult, and 3 young sp.— 
2306, 5 sp. adult, decollated, varying in pattern.—2307, 1 sp. 
with its operculum, and 1 separate operculum. 
614. Niri1peLnna ————,, sp. ind. 
ri 
Tablet 2308 contains an apical and a basal fragment of a 
species perfectly smooth except the basal strie, with purple in 
large irregular patches or zigzag lines. 
Tablet 2309 contains a fragment like the last, and possibly 
conspecific, but crowded with the most minute radiating 
striule. 
Hab.—Mazatlan; extremely rare, off Spondylus; Z’pool Col. 
