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 ; els^ 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 striae. Lab rum with 9-12 teeth, of which 

 that next the shoulder is elongate. Labium broad, smooth. 

 The operculurn is very long, and thin, large for the shell, 

 horny, with faint ridges of growth. The perfect specimen 

 measures long. '55, long. spir. '34, lot. '19, div. 28. 



An ordinary sp. ., '46, '23, '22, 32. 



Hob. Java Seas, M. Lesckenault, Lamarck. Ascension Isl. 

 Quoy <$f G-aimard. Corea, Kiener. Guinea, Tarns. Cuba, 

 Sagra. Barbadoes, Catting. Panama, under stones, very 

 common, Owning. 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. NITIDELLA , sp. ind. 



Tablet 2308 contains an apical and a basal fragment of a 

 species perfectly smooth except the basal striae, with purple in 

 large irregular patches or zigzag lines. 



Tablet 2 309 contains a fragment like the last, and possibly 

 conspecific, but crowded with the most minute radiating 

 striulse. 



Hob. Mazatlan ; extremely rare, off Spondylus ; IS pool Col. 



