STYLIFEU. 



167 



microscopic atoms and another, he often felt that he coukl 

 liave safely challenged their definition by the authors 

 with the shells themselves before them. The following will 

 therefore be found a very summary account of the genera 

 and species : — 



I. AcLis has a long retractile proboscis, long thin tenta- 

 cles, with the eyes at their thickened bases ; the foot tongue- 

 shaped ; the shells are like the minute TurrUella. 



A. ascaris is pyramidal, spirally ridged. 

 A. stipranitida is like it, but with a perforation behind the 

 aperture, and the upper part of the whorls not ridged. 

 A, unica : very long and narrow, finely decussated. 

 A. nitidissima: like A. miica, but nearly smooth. 



II. Stylifer.— The httle molluscs to which this generic 

 name was first applied by Mr. Broderip are found living pa- 

 rasitically in the body of star-fish, in which they burrow, 

 and on which they feed. Cunningly boring their hole in a 

 pulpy spot, chosen so as to avoid the vital parts of the tor- 

 tured Asterias, they live and fatten in security upon his 

 substance. 



The Stylifer astericola, found living on the coast of Bor- 

 neo, as described by Mr. A. Adams, has two elongate, su- 

 bulate tentacles, with the eyes sessile near the outer side of 



