some new and peculiar Mollusca. 321 



of Biscay, 718-1095 fms. 'Challenger' Expedition, west of 

 Fayal, Azores, 1000 fms. 



Velutinidae. 



Pilidium radiatum^ Sars. 



Capulus radiatiis, Sars, Beretninp; om en i Sommeren 1849 foretagen 

 zoologisk Reise i Lofoten og Finmarken, p. 64 (1850), 



Body milk-wliite : mantle very thick, covering one third 

 of the mouth of the shell : tentacles club-shaped, slender, com- 

 pressed or flattened, contractile, closely striated across at the 

 tips, and thickly covered with short cilia : e^jes placed on 

 small bulbs near the outer base of the tentacles: foot oblong, 

 proportionally small, rounded and double-edged in front, and 

 bluntly pointed behind. Very sluggish, and exudes a large 

 quantity of stringy slime. Adhering to a dead shell. 



Station 5, 57 fms. (a single specimen) ; Holsteinborg, 12 fms. 

 (a young shell). Spitzbergen (Torell) ! Finmark (M. Sars) ! 

 Sea of Okhotsk (Middendorff) ! Japan (A. Adams). Aleu- 

 tian or Fox Islands, N. Pacific (Dall) ! Fossil : Uddevalla 

 and Kurod, Sweden (Hisinger, J. Gr. J.) ; Moray Firth (Robert 

 Dawson) ! Montreal (Principal Dawson). 



Synonyms : Pilidium commodum^ Middendorff, 1851 ; Pilis- 

 cus commodus and Piliscus prohus^ Loven, 1859 ; Capulus 

 dilatatiis and C. depressios, A. Adams, 1860 and 1864. 



Through the kindness of Professor G. O. Sars and of Dr. 

 L. von Schrenck I have lately been able to compare with my 

 specimens from Davis Strait the typical specimens of Capulus 

 radiatus and Pilidium commodum from the Christiania and 

 St. Petersburg Museums. All of them exactly agree with 

 each other, as well as with my fossil specimens of Piliscus 

 prohus (Lovdn) from Uddevalla. Sars's Norwegian shell and 

 mine from 57 fathoms in Davis Strait are marked with coloured 

 streaks, which radiate from the apex or crown, while the others 

 are not streaked or coloured. 



The generic name Pilidium was published by Middendorff 

 in his ' Malacozoologia Rossica,' 1849. Professor Forbes gave 

 the same name for Tectura fulva in the Report of the British 

 Association for 1849, published in 1850 ; and Pilidium was 

 described in 1853 by Forbes and Hanley as their generic name 

 for the last-mentioned shell. The late Professor Sars substi- 

 tuted, in 1858, the generic name Capulacmcea for his Capulus 

 radiatus. Professor Lov^n, in 1859, proposed Pi7^scMs. Pos- 

 sibly Capulus fallax of Mr. S. V. Wood (a Crag fossil) may 

 be another species of Pilidium. 



