GASTEROPODA. '279 



CLASS GASTEROPODA. 



ORDER INFEROBRANCHIATA. 



Genus Pleurobranchus. 



" P. plumula, Malbay, County Clare, very rare," Prof. Harvey. 



P. memhranaceus, Mont, (sp.) 



Mr. John Humphreys of Cork has infonned me that a specimen occur- 

 red to Mr. Beevor and himself when dredging in the harbour ; " the 

 animal was large, about 2 inches in length, and the shell a very good 

 one ;" — the species had not before been met with by Mr. Humphreys. 

 Belfast Bay and off Groomsport, Mr. Hyndman. 



ORDER TECTIBRANCHIATA. 



Ge7ius Aplysia. 

 A. depilans, Linn, Generally distributed in Ireland. 

 A. punctata, Cuv. General. 

 A. nexa, Thompson. 



Animal elongate, deep carmine-red, mantle bordered with black. Length 

 1 inch, much elongated, foot very narrow ; tAVO black eyes anterior to, 

 but a little distant from, the base of the dorsal tentacula. 



Colour deep carmine-red, occasionally with a few minute white spots ; 

 mantle and anterior tentacula bordered with black, dorsal tentacula tijjped 

 with black. 



The specimen of this Aplysia was dredged on the 26th of August, 1844, 

 off Castle Chichester, Belfast Bay, by Mr. Hyndman — depth 6 to 10 

 fathoms. The characters which this beautiful little Aplysia has in com- 

 mon with A. depilans need not be given. Whether we consider it dis- 

 tinct from, or a mere variety of, that species, it differs from it in being of 

 a more elongate form, in colour, and in having the mantle, &'C., bordered 

 with black. 



From a single example only I should not venture to describe it as a 

 distinct species, but on sending my specimen (its characters being first 

 noted down) alive in sea-water to Newcastle-upon-Tj-ne, for Mr. Alder's 

 examination, he replied, that an Aplysia similar in form and colour had 

 been taken by him at Torbay in Devonshire, about two years before, but, 

 not having had much opportunity of studying the genus, he felt uncertain 

 whether it should be considered a variety of an A. depilans, or a distinct 

 species. Neither do I feel certain on this ])oint, until an equally small A. 

 depilans be had for comparison ; but it seems to me better to describe and 

 figure the form in question, and leave the matter of species for future 

 decision, than to be altogether silent on the subject. A coloured di'aw- 

 ing of Mr. Alder's specimen being kindly transmitted to me, it was found 

 to represent mine exactly, except in the very trivial difference of having a 



