ZOOLOGICAL AND BOTANICAL ASSOCIATION. 69 



fixed upon the genus the stigma of the fronti nulla fide*, and subse- 

 quent naturalists, following his lead, seem to have credited the common 

 C. pumicow with an unlimited variability. Mr. Thompson himself in- 

 clines to regard the C. ramulosa and C. Skenei as two of its multitudi- 

 nous "states" (vol. iv., p. 470). 



An examination of the minute characters will at once show that this 

 view is quite untenable, and that " dissimilarity of habit'* is by no 

 means the only point which separates them. 



Many crustaceous forms seem to have been overlooked from their re- 

 semblance, on casual inspection, to the C. pumicosa. 



The Trinity College collection and Mr. Hyndman's dredgings fur- 

 nish many specimens of Cellepora ; but I have not been able to satisfy 

 myself fully about them, and content myself for the present with re- 

 cording one or two of the most marked forms. 



The Antrim deep-water dredgings have also yielded a large number 

 of the Cyclostomata, chiefly belonging to the genera Tubulipora and 

 Alecto; but these I am obliged to reserve for future examination. One 

 fine new Alecto is described in a subsequent part of this paper. 



Some of the recently discovered Polyzoa are exceedingly minute 

 and inconspicuous, and may readily escape detection. Such are the 

 Buskia nitens (Alder), which seems to be very generally distributed, 

 and which occurs in the Isle of Man; and the Scruparia clavata (miki), 

 which has been found both in England and Scotland. 



There is every probability that close investigation would add these 

 and many more of the minuter forms to the Irish list. I venture also to 

 prophesy that the beautiful Mimosella gracilis, hitherto found only on 

 the shores of Devon and Cornwall, will be met with in some of the more 

 sheltered bays in the south of Ireland. It must be sought in the Lami- 

 narian Zone, and where the Halidrys siliquo&a is abundant — the favour- 

 ite haunt of the Yesicularian Polyzoa. 



Mr. Thompson's catalogue enumerates 145 species of Hydroida and 

 Polyzoa as natives of Ireland. A strict revision, however, with our 

 present knowledge, would remove several of these from the list. In this 

 paper 42 additional species are recorded, bringing up the whole number 

 of Irish (published) species to 187. 



It may stimulate the zeal of Irish collectors to mention that more 

 than 100 British forms have not yet found a place in the Fauna of their 

 country, while there can be little doubt that careful research would bring 

 to light large numbers of new species. 



