112 LlTTORINID.li. 



not a little of R. auriscalplum) the mouth only occupies 

 two-fifths, at most, of the entire length, and the margina- 

 tion of the lip is almost obsolete. 



The animal has a pale or slightly brown -tinged yellow 

 head and snout, with white subulate tentacles and spaces 

 round the eyes. The central or contracted portion of 

 the sides of the foot are coloured with dark purple, as 

 also are the well-developed lateral lobes. The foot is 

 slightly squared in front, pointed behind, and bears be- 

 hind the opcrculigerous lobe a conspicuous white caudal 

 filameut. 



The favourite habitat of this species is on the leaves 

 of Zostera in sandy or muddy places. It is chiefly found 

 on our southern and western shores. The solid variety 

 occurs in three fathoms water, near the pier at Ryde, 

 in the Isle of Wight ; the smooth form is chiefly found 

 where there is an intermixture of mud, as at Tenby, ^lar- 

 gate, and Weymouth (S. H.). At Southampton it is abun- 

 dant in from one to three fathoms water (E. F.) Fal- 

 mouth ; coast of South Wales ; Oban, and Loch Carron, 

 in Scotland, (Jeffreys). In various localities around the 

 Irish coast (W. Thompson). 



It ranges from the shores of Norway to the Mediter- 

 ranean. 



