A NEW PARASITIC MOLLUSK OF THE GENUS EULIMA. 



By Paul Bartsch, 



Assl.'<tant Cunitor, Division of Mollusks, U. S. National Masmm. 



Mr. Austin H. Clark recently called my attention to nJ'^/IJhuiiound 

 parasitic upon a deep-sea crinoid {Ptilocrmus j/i/matu!^ Clark). The 

 specimens were dredged by the U. S. Bureau of Fisheries steamer 

 Alhatross at Station 3312, in 1,588 fathoms, off British Columbia. 



These specimens are remarkable for a number of reasons; they rep- 

 resent a truly parasitic species, a fact I believe not heretofore noted in 

 this genus. All three of the individuals found had the proboscis 

 deeply inserted in the side of the body of the crinoid, and it was neces- 

 sary to sever it in order to release the shell. Some of the crinoids' 

 show a number of punctures, probably all made by the Eulima. 



The parasitic habit, the texture, and weak malleations of the surface 

 recall certain forms of StyVifei\ but the absence of the mucronate 

 apex and the presence of the operculum place it in Eulima. 



EULIMA PTILOCRINICOLA, new species. 



Shell elongate-conic, thin, polished, transparent, tinged with bluish- 

 white (the dried animal showing through the upper whorls as a gran- 

 ular golden-yellow mass). Whorls eleven, increasing regularlv in 

 size, decidedl}' rounded, with the surface weakly malleated, having 

 a few feebly developed varices which appear at irregular intervals 

 as^ narrow opaque vertical l)ands. Sununit of the whorls closely 

 appressed to the preceding turn, the extreme edge forming a slender 

 spiral sutural band. Last whorl quite strongly inflated basally. 

 Periphery and base well rounded, marked like the spire. Aperture 

 moderately large, suboval; outer lip thin, evenly curved; columella 

 slender, vertical, slightly reflected; parietal wall covered by a thin 

 callus. Operculum thin, corneous. 



Proceedings U. S. National Museum, Vol. XXXII— No. 1 548. 



