488 MAZATIiAN UNIVALVES 



is liowever by no means constant in colour and markings ; nor 

 are the Atlantic skells more so. One perfect adult specimen 

 was found, -witb. 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 a light greenish horn colour. 

 Base with spiral strise. 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 lo)ig. "55, long. spir. "34, lat. "19, div. 28". 



An ordinary sp. ., '46, „ -23, „ -22, „ 32°. 



Hah. — Java Seas, M. Leschenau,lt, Lamarck. — Ascension Isl. 

 Quoy Sf Gaimavd. — Corea, Kiener. — G-uiuea, Tarns. — Cuba, 

 Sagra. — Barbadoes, Catting. — 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 ; I! 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. NiTiDELLA , sp. ind. 



Tablet 2308 contains an apical and a basal fragment of a 

 species perfectly smooth except the basal stria;, 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 

 striula?. 



Hah. — Mazatlan ; extremely rare, off Spondylus ; L'pool Col. 



