244 



Shell Life 



Poached Egg 



thrown well up over it, and only a narrow streak of 

 the shell shows between. The shell is little less than 

 half an inch in length, and occurs locally all round 

 our islands on sandy ground in from 12 to 85 

 fathoms. The white foot is speckled with orange, 

 pink, and black, to harmonise with this ground, whilst 

 the mantle-lobes are dotted with purple-brown marks 

 and studded with pale yellow tubercles in imitation 

 of the zoophytes on which it feeds. 



The Poached Egg {Ovida paiula) has a moutli that 

 is much longer than the shell-proper, and it appears 



to be all body-whorl. But 

 if we look again at the 

 Margin-shell and imagine 

 the outer lip extended to a 

 greater length than the 

 spire, the result would be spindle-shaped, much like 

 the shell of the Poached Egg when freed from the 

 mantle-lobes. This shell is thin, glossy, 

 and almost transparent, whitish with a 

 tendency towards yellow. Young speci- 

 mens exhibit a brief spire within the canal 

 formed by the extension of the outer lip 

 above, but the adult shell is of the form 

 shown in this figure. Tlie animal is yellow- 

 ish white tinged wdth brown ; the mantle- 

 lobes, which sometimes completely cover 

 the shell, are marked with brown transverse lines 

 and small spots. It feeds upon the zoophyte Tiihu- 

 laria indivisa, and lives among the colonies of its 

 victims, the brown stripes of the mantle-lobes helping 

 to disguise it from its own enemies by assimilation 

 to the clustered tubes. Its distribution is not general, 



