272 MOLLUSCA. 



loured. In one of them the anterior portion of the foot was margined 

 with a line or band of a fine blue colour. 



D. rcpanda. 



Alder and Hancock. Annals Xat. Hist. vol. ix. p. 32. A specimen of 

 this Doris was found between tide-marks at Roundstone, County Galway, 

 in July, 1840. Dr. Ball, Prof. E. Forbes. W. T. 



D. hUamellata, Linn. 

 I have obtained this between tide-marks, at the island of Lambay, off 

 the Dublin coast, and by dredging in about ten fathom water, in Belfast 

 Bay. A specimen which was particularly examined was found to agree 

 with Dr. Fleming's description of D. verrucosa in the number of bran- 

 chial processes, which are 24, and in their arrangement being somewhat 



" semicircular," in a broadly horse-shoe form, thus ^), In Dr. John- 

 ston's specimens the branchial processes seemed " not much to exceed 

 twelve," and were disposed in an " uninterrupted circle." Annals, vol. i. 

 p. 55. Although the precise number of these organs is of no specific 

 value, the difference alluded to is so great as to be worthy of attention. 

 In a specimen from Newhaven, near Edinburgh, favoured me by Pro- 

 fessor E. Forbes, these processes are twenty in number. 



D. affinis, Thompson. 



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 re- 

 sembling those of D. tiiberculata ; cloak covered with long stout tuber- 

 cles varying in size, the largest along the sides, and f of a line in height, 

 generally of equal breadth throughout, but occasionally expanding to- 

 wards the end, which terminates in a mass or fasciculus of spicula, con- 

 spicuous under a low power of the lens, and giving to them the appear- 

 ance 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 D. hilamellata, and the space within 

 them likewise covered with tubercles. 



This Doris approaches D. hilinneUata more nearly than any other Brit- 

 ish species, and would perhaps be regarded by some authors as only a 

 variety of it; for this reason I have named it a^ffinis, to mark that as a 

 species it may be viewed with some suspicion. Compared with D. hila- 

 melhita, the D. ajfinis has more solidity, is somewhat more depressed, its 

 outline of body less elegant, margin of the cloak narrower, tentacula and 

 branchise apparently less developed, and instead of the pretty rounded 

 termination which the tubercles of D. hilamcUafa generally present are 

 fasciculi of spicula, and these not so tastefully disposed over the surface 

 of the cloak as in that species : in all respects it is a less attractive 

 animal. 



In the month of December, 1837, I obtained three specimens of this 

 Doris from among oysters di-edged at Greencastle, County of London- 

 derry. 



D. Ulidiana, Thompson. 



On the 17th of February, 1840, 1 procured three specimens of this Doris 



