238 STYLIFERIDiE. 



oblong, entire ; inner lip distinct, callous, slightly sinuous 

 in the middle ; outer lip flexuous. 



Ex. L. bilineata. Alder, p\. 25, fig. 3. Shell, L. Met- 

 calfei, A. Adams, fig. 3, a. 



The most curious circumstance about the type of this 

 genus is the fact of its being compressed from before 

 backwards, with a varix on each side, as in Bursa and 

 Pytlda. 



Species of Leiostraca. 



acuta, Soiv. Mindorensis, Adams and 



bilineata, Alder. Reeve. 



bivittata, H. and A. Adams solitaria, C. B. Adams. 



(bilineata, Adams and subulata, Donov. 



Reeve). uuilineata, Adams and 



fulvociucta, C. B. Adams. Reeve. 



Metcalfei, A. Adams. varians, Sow. 



Fam. STYLIFERID^. 



Lingual membrane ? Tentacles slender, subulate, 

 simple ; eyes sessile at the outer bases of the tentacles. 

 Mantle enclosed. Foot linguiform, forming an elongated 

 anterior lobe, rudimentary behind. 



Operculum none. 



Shell thin, subulate or subglobose ; aperture entire ; 

 columella simple. 



These singular animals are parasitic in the skins of 

 Star-fishes, burrowing beneath the surface, and pro- 

 ducing tumours, often of considerable size. When re- 

 moved and placed in water, they do not appear to possess 

 much locomotive power, but extend the tongue-shaped 

 foot and use it as an exploring organ. 



