STILIFER. 191 



the vent or anal orifice of Echinoderms, and that some 

 which I watched with close and almost unremitting 

 attention for many hours, although they were most lively, 

 nestling or slowly crawling about among the spines of 

 an Echinus, never attempted to touch with the proboscis 

 or mouth either the protruded suckers or the pedicel- 

 larias of the Echinus, or any part of its investing mem- 

 brane. As far as I have been able to observe, the Sti- 

 lifer does not put its host to the slightest inconvenience. 

 No Stilifer has been noticed in any other habitat ; and 

 its connexion with seaeggs and starfishes is evidently 

 neither accidental nor merely for the purpose of shelter. 

 The suctorial proboscis, as well as the want of a den- 

 ticulated tongue in S. Turtoni, strengthens the sup- 

 position that its food consists of extremely soft or semi- 

 fluid matter, and not of organisms which have any degree 

 of solidity. Dentalium, which preys on hard-shelled 

 Foraminifera, has a complicated lingual apparatus ; and 

 even the little Rissoa, that feeds on seaweeds, often of 

 the most delicate and filmy texture, possesses a pair of 

 horny jaws, besides a tongue armed with a strong cen- 

 tral tooth, flanked on each side by a formidable row 

 of serrated lateral teeth. Stilifer has nothing like 

 a jaw or tooth. For these reasons I do not consider 

 Stilifer a true parasite, nor yet an epizoic organism, like 

 Montacuta substriata, deriving its nutriment from the 

 vicinity of the animal to which it attaches itself but as 

 holding an intermediate relation. Its scavenger-habits 

 are not unlike those of the dung-beetle. I would recom- 

 mend those who care to pursue this inquiry to consult 

 Hupe's paper in the ( Revue et Magasiii de Zoologie ' 

 for March 1860, and Fischer's monograph on the genera 

 Stilifer and Entoconcha in the ' Journal de Conchylio- 

 logie ' for April 1864. They may also see in the ' Report 



