Mr. Thompson on the Mollusca of Ireland. 85 



1812, on the shore towards the entrance of Belfast Bay ; and 

 Dr. J. L. Drummond informs me, that about the same time 

 he procured a Doris here equalling a hen's egg in size, and 

 which he considered to be of this species. At Youghal 

 (county Cork,) it has been taken by Mr. R. Ball, and to this 

 gentleman and myself has occurred at the island of Ireland's 

 Eye, off the Dublin coast. Mr. Geo. J. Allman, of Bandon, 

 has favoured me with specimens procured by him at Court- 

 masherry harbour, county of Cork, where he states that the 

 species is common. The Irish specimens I have seen were 

 generally straw-coloured. In one of them the anterior por- 

 tion of the foot was margined with a line or band of a fine 

 blue colour. 



Doris affinis, mihi. 



Body elongated, equally rounded at both ends, depressed, above 

 closely studded with stout prolonged tubercles, orifices of tentacula 

 without sheaths ; branchial processes short, numerous, pinnate. 



Length 1^ inch, breadth equal to half the length ; of a very pale 

 straw colour ; tentacula without sheaths, short, lamellate, in all 

 respects resembling those of Z). tuberculata ; cloak covered with 

 long stout tubercles varying in size, the largest along the sides, 

 and I of a line in height, generally of equal breadth throughout, 

 but occasionally expanding towards the end, which terminates in a 

 mass or fasciculus of spicula, conspicuous under a low power of the 

 lens, and giving to thsm the appearance of a spinous armature ; 

 margin of the cloak moderately broad, its under surface granulated; 

 space between it and the foot, and also this latter smooth ; branchiae 

 short, pectinate, about 18 in number, disposed in a broadly horse- 

 shoe form as in Z>. bilamellata, and the space within them likewise 

 covered with tubercles. 



This Doris approaches D. bilamellata more nearly than any 

 other British species, and w ould perhaps be regarded by some 

 authors as only a variety of it ; for this reason I have named 

 it affinis, to mark that as a species it may be viewed with some 

 suspicion. Compared with D. bilamellata, the D. affinis has 

 more solidity, is somewhat more depressed, its outline of 

 body less elegant, margin of the cloak narrower, tentacula 

 and branchiae apparently* less developed, and instead of the 



• The specimens were not attended to when living, consequently we must 

 remain in uncertainty about some characters. 



