PROCEEDINGS OF SOCIETIES. 97 



size, and its still more slender, Tern-like bill. These references are shown to 

 prove the confusion that might possibly arise in the distinguishing of the alliances 

 of birds in the immature plumage, more especially those of the Laridse, or the gulls ; 

 and, as Wilson most truly remarks on the much-varied species L. ridibundus, 

 " that less confusion would arise among authors if they would occasionally abandon 

 their accustomed walks, their studies, and their museums, and seek correct know- 

 ledge in the only place where it is to be obtained in the great temple of Nature." 

 No discussion having arisen on this subject, 



Mr. Hopkins read the following paper on the 



OCCURRENCE OF IANTHINA COMMUNIS AND SPIRULA PERONII AT KILKEE. 



At your last meeting, when I had the pleasure of adding a few specimens of 

 lanthina communis to your collection of Irish mollusca, I was requested, by Mr. 

 Andrews, your secretary, to give a short paper on this interesting shell, and now 

 beg to bring the occurrence of this and other species on the west coast of this 

 country under your notice. 



In the month of August, 1851, being at Kilkee, which I knew to be a locality 

 where the lanthinae are of tolerably frequent occurrence at certain seasons, I de- 

 termined to watch closely for them. The wind was N.W., and, after three days 

 had elapsed, I was rewarded with finding the lanthina communis in large numbers, 

 in company with five specimens of lanthina pallida and three of Spirula Peronii, 

 together with quantities of the Velella and several species of Anatifa and Vitrea. 

 From the circumstance of the lanthina being drifted in after N.W. winds, it is 

 evident that, though a native of the warmer latitudes of the ocean, these indivi- 

 duals must have been floating fully as far, if not farther north than Kilkee. 



The best locality for them I found to be at the south side of the entrance to the 

 bay, on the Duggana reef, where I took them alive, immediately after high water, 

 floating on the surface, in pools, situated in clefts of the rock. I would here 

 remark, that from the coast being so rocky, more than two-thirds of the specimens 

 I obtained were, unfortunately, irretrievably damaged. 



The float or vesicular appendage by which the lanthina is buoyed up on the 

 surface of the ocean has occasioned many very conflicting opinions ; among others, 

 I will refer to Whitelaw and Walsh's " History of Dublin" (London, 1818), in the 

 appendix to which is a catalogue of Irish shells, and, from a note to Helix janthina, 

 by which name it was then known, I take the following extract. Brown, in his 

 ""Account of Jamaica," gives the following account of this shell : " Purple ocean 

 shell. The creature which forms and inhabits this shell is a native of the ocean, 

 and lives frequently many hundred leagues from any land ; but having met with 

 many of the kind between Bermuda and the Western Islands, in my voyage from 

 Jamaica, it enables me to communicate the following account of them : The crea- 

 ture probably passes the greater part of life at the bottom of the sea, but rises 

 sometimes to the surface, and, to do so, is obliged, pischim more, to distend an 

 air-bladder, which, however, is formed only for the present occasion, and made of 

 tough, viscid slime, swelled into a vesicular, transparent mass, that sticks to the 

 head of the animal, at the opening of the shell. This raises and sustains it while it 

 pleases to continue on the surface ; but, when it wants to return, it throws off its 

 bladder, and sinks." 



Though, as I believe, this account of Brown's coincided with the generally re- 

 ceived opinion at that time, it will be found incorrect, on referring to Forbes and 

 Hanley, who, in their work on the British mollusca, remark that Cuvier observed 

 there was no anatomical connection between the two bodies i.e., between the 

 animal and the float and this was confirmed by Dr. Coates, who, in the fourth 

 volume of the " Journal of the Academy of Natural Sciences of Philadelphia," 

 gives an interesting account of his experiments on the float in the living animal. 

 He found that it was entirely secreted by the foot, and that when a portion was 

 removed, the injury was rapidly repaired. 



After having quoted such high authority, it may appear superfluous for me to 

 remark, it is my opinion that were the lanthina capable of inflating and exhausting 

 this float, it would never be found on our coasts in any profusion, as it would 



