. sl 
ON THE FAUNA OF IRELAND. ~ 25] 
appeared. Since the latter period the British catalogue of species belonging 
to this beautiful order of Mollusca has been greatly augmented by the labours 
of Dr. Johnston*, Mr. Edward Forbes}, Mr. Aldert, and Mr. Hancock, and 
above all by the two latter gentlemen, who, studying the subject conjointly, 
have by the very complete and philosophical manner in which their investiga- 
tions were conducted, thrown the greatest light upon the order Nudibranchia. 
The number of British species now known is sixty-five §, of which twenty- 
three have been met with in Ireland; to these latter are to be added eleven 
species unknown as British, making the number of Irish altogether thirty-four 
—of these eleven, two constitute new genera, and the remaining nine are, 
with the exception of the Doris muricata of the ‘ Zoologia Danica,’ believed 
to be new species and are indicated in the preceding catalogue by the initial 
“(I.)” All of the British genera but two—#ubranchus and Calliopea ||— 
have been procured on the Irish coast; the former is known only from its 
occurrence in one instance to Mr. Forbes in the Isle of Man; the latter was 
as a British genus announced for the first time at the present meeting: upon 
the Irish coast only the new genera Proctonotus and Alderia have been ob- 
tained. The genus Proctonotus, together with two new species of Holis and 
seven species known as British, but not hitherto as Irish ], were added to our 
catalogue by Mr. Alder last autumn during little more than three days’ exami- 
nation of the Dublin coast: within a similar time about equally good results 
have been obtained by Mr. Hyndman and myself in another locality, Strangford 
lough; instances which show how much may be done in the Nudibranchia with- 
in a very limited period. Mr. Alder (who in conjunction with Mr. Hancock is 
engaged in a monograph of the whole of the British species belonging to this 
order) having expressed a desire to examine my specimens noticed in the fifth 
and seventh volumes of the ‘ Annals of Natural History,’ they were at once 
placed in his hands. This has unexpectedly proved serviceable to myself on 
the present occasion, as I have had the benefit of his revision of what had 
been written on the Irish species. Mr. Alder’s information on the subject so 
far surpasses my own, that his opinion has been implicitly followed through- 
out the preceding catalogue with respect to what are good species, what only 

varieties, &e. Distribution. 
S|./s/4 
Class GASTEROPODA. EIe : 3 
Order Inferobranchiata. bi ibe 
Pleurobranchus plumula; Bulla plum. Mont. .......sscceccseesceseecseceeoeeslesefaes 2 
nA ? membranaceus ; Lamellaria memb. Mont. ...........cc.seleceleee raelia 
Are the British species of the order Inferobranchia. 
Class GASTEROPODA. 
Order Teetibranchiata. 
Aplysia depilans, Lin.......0..00 Bea Adcaddanaddcsuvesasisasedpsccsaed ssc bcheudises sgeltegsl al 
PMDMOCLALAs CUUL Vancnddantencncsmeevs scesestonovaaess iaswadcess@baou nals waa fae Page| sec 
* Annals Nat. Hist. vol. i. 
+ Annals Nat. Hist. vol. v. p. 102 et seq.; Malacologia Monensis, Report, British 
Association, 1839, p. 80. 
~ Annals Nat. Hist. vol. vi. ix. xiii. 
§ Messrs. Alder and Hancock have contributed about twenty-five species to this 
number within the last two or three years. 
|| Mr. Alder marks Doris bifida, Mont. (which has been obtained in Belfast bay) 
with doubt, as belonging to this genus. Montagua he considers not to be generically 
distinct from Holis, Calliopea dendritica—the British species—is described in Annals 
Nat. Hist. for Oct. 1843. 
{| Two of these species, obtained by Dr. Geo. J. Allman on the coast of Cork in 
August 1842, have been forwarded to me since the preceding was written. 
