282 PYRAMIDELLIDiE. 



in certain aspects gives them a clavate appearance, and at 

 the under part they are aspersed with minute sulphur dots. 

 The eyes are large, very black, imbedded in the skin, a 

 little below the origin of the tentacnla at the internal 

 bases. The foot is very short, strictly truncate in front, 

 scarcely auricled, with, at half extension, a very rounded 

 posterior termination ; but on the march it tapers to a 

 lanceolate point. It carries, at a little distance from the 

 terminus of the pedal disk, on a simple upper lobe, a 

 slightly arcuated suboval light horn-coloured operculum, 

 which has its columellar edge raised and reflected out- 

 wardly throughout its length, the nucleus being in the 

 centre, from whence the striae of increment radiate con- 

 spicuously to the outer margin. Its structure altogether 

 is similar to the operculum of Jeffrey sia diaphana. The 

 foot, above and below, the body generally, and the neck 

 and head, are of a rather opake white ground colour, 

 sprinkled irregularly, and not very thickly, with bright 

 sulphur minute points. The animal is lively, moves with 

 celerity, displays its organs, and swims on the back. It 

 is an inhabitant of the finer algae of the pools of the lower 

 levels of the littoral line at Exmouth. It is a most poly- 

 morphous species, as out of nearly one hundred specimens, 

 scarcely two are alike ; varying in tumidity, length, and 

 colour ; indeed, every hundred yards of coast has its 

 variety." — Clark, MSS. 



