CRANIA. 367 



by a few somewhat radiating obscure groove-like inden- 

 tations. The lower or attached valve, which is a mere 

 coating of shelly matter, is not larger than the other, but, 

 on the contrary, is entirely concealed by it. Its lower 

 scars are large, ovate, and somewhat angular above ; the 

 upper ones are separate, ovate, and almost linked together 

 in the middle ; the rostellum or noselike intermediate 

 portion is obtuse ; the disk palmato-radiated ; the margin 

 thickened and somewhat scabrous. The diameter varies 

 from half an inch to eight lines. 



The animal was first figured and noticed by Otho 

 Frederic Muller, who well styled it, " Vermis singularis- 

 simus," yet persisted in regarding it as an anomalous form 

 of Patella. The arms are extended horizontally, each 

 forming a rather short, graceful, plume-like curve, the 

 fringed side being outermost. The fringes are long and 

 rather stiff, and can be extended slightly beyond the shell. 

 They are of a fleshy-white colour. When the upper valve 

 is removed, the fringed arms are seen lodged in it. On 

 the under-valve the ramifying ovaries, which are of a 

 tawny hue, remain. 



This curious bivalve was first added to the British lists 

 by Dr. Fleming, who found it adhering to stones, from 

 deep water in Zetland ; since then it has been taken 

 abundantly in several localities, chiefly on the west coast 

 of Scotland. Off Arran in twenty fathoms (Smith) ; 

 Loch Fyne in thirty to eighty fathoms, plentiful, on 

 stones ; off Mull in twenty and ninety fathoms ; off 

 Lismore in from twenty to thirty fathoms ; off Arma- 

 dale in eighteen fathoms ; off Copenhaw-head, Skye, in 

 forty fathoms ; on the Ling banks off Zetland in fifty 

 fathoms (M'Andrew and E. F.) ; Loch Alsh, Loch 

 CarroD, Ullapool, Oban, east of Lerwick, in forty fathoms 



