DUBLIN NATU&AL HI8T0BT 80CIXTT. 1S5 



who have read Professor Haughton's paper on the Tides know that 

 rapid currents prevail here, and from this it results that the bottom of 

 the sea in the gieat depths is generally rocky. It may be that the Pleis- 

 tocene beds fonnerly liere have been torn up, and have formed the banks on 

 which these shellti are found. The mixture of northern and southern 

 Bpecies here was very curious. He might mention the fact, that Tapes 

 aurea, which had occuired not uncommonly to Dr. Kinahan at Carrick- 

 fergus, was extremely rare on the opposite, or Dovra coast. Mactra 

 tuhti'unoata there was extremely common, and two other species, which 

 were rare at Caiiickfergus — M. stultorvm and M. solida. 



Mr. Gilbert Sanders mentioned his having found, some years ago, 

 one or two specimens of the 'Topes mirea at Portmamock. The shells 

 were certainly not living, but appeared fresh. Pleistocene beds of tiem 

 occurred in that neiglibourliood. 



Dr. E. Perceval Wright confirmed the peculiar distribution in the 

 northern districts among the Actinise, some of which extended from 

 Youghal, round the west coast, as far as Belfast, but were not found in 

 the intervening eastern district. 



Rev. Professor Haughton observed, that as Mr. "Waller had alluded 

 to the subject of cuiTents, he would wish to make a few remarks. Two 

 strong currents— a northern and a southern — meet in the Irish Channel. 

 The strength of the northern cuiTcnt is such that it must offer an 

 insurmountable bar to the passage of southern species northwards ; but 

 at the same time the very strength of the current would lead one to 

 expect just such a sea bottom as had been described by Mr. "Waller — a 

 rocky bottom, from which all the soft deposits were torn away, except, 

 perhaps, in a few hollows. The chalk shells found in the drifts about 

 Dublin and other places on the east confirm this idea, these being 

 more abundant near the edge of the sea. He saw no reason why the 

 tom-up drift might not be carried even down as far as the Isle of Man. 



De. E. Peeceval "Weight read the following — 



NOTES ON THE lEISH NTJDIBEANCHIATA. 



While engaged for the last few years in investigating the Tunicata of 

 Ireland, I have from time to time recorded in my note-book the several 

 species of NudibranchiateMollusca that have occurred to me; and in order 

 to call the attention of Irish naturalists to this branch of zoology, I 

 would append a list of all that are known to me up to the present moment 

 as frequenting our coasts. In the late W. Thompson's ** Report on the 

 Invertebrate Fauna of Ireland," there were, deducting sjTionjnns, twenty- 

 eight species recorded. The number in the list appended is thirty-eight, 

 which is about one-fourth the number of the known British species; 

 but I have very little doubt that the slightest attention paid to this at- 

 tractive group would very considerably enlarge it. In a late excursion 

 with my friend. Professor J. Reay Greene, around the south and south- 

 west coasts of Ireland, several most interesting forms were discovered: 

 among them I would most particularly mention E0U4 Farrani. This 



