Clare Island Survey — Marine Mollusca. %%, 23 



ment (Kay Soc, 1910) to Alder and Hancock's Monograph of the 

 Nudibranchs, and the crystalline point of the verge which he failed 

 to trace in his Millport specimen was obvious in the Portarriv examples, 

 and agreed precisely with Alder and Hancock's figure (loc. cit., PI. XX, 

 fig. 6). 



The particulars, none of them of any great importance, in which the 

 Clare Island Actaeonia differed from Alder and Hancock's description 

 and plate, were the absence of any distinct lateral ridge, the greater 

 prominence of the visceral hump, and the irregularity of the pale 

 lateral markings, which formed rather a longitudinal series of yellow 

 blotches than a regular line of tubercular spots. The heart-beats were 

 clearly visible through the light-coloured visceral hump, numbering 

 from 50 to 60 per minute, and so vigorous as to set up a distinct rhythmic 

 alteration in the outline of the hump. 



In captivity, the Clare Island Actaeonias deposited three spawn-clusters 

 irregularly oval in shape, with from 3 to 12 large eggs, about - 5 mm. 

 in their longest diameter. The nuclei were bright orange and immersed 

 in a milky envelope which became perfectly clear in the later stages 

 of development. In one of the clusters the eggs within about 14 

 days from extrusion developed so far as to show the eye-spots dis- 

 tinctly in the revolving larvae, though the larvae did not succeed in 

 breaking free from the egg. ~No sign of a shell or of any veliger 

 structure appeared at any stage of the development, which, so far, agreed 

 with Pelseneer's account of the development of Cenia Cocksii. 



Sir C. Eliot (loc. cit., pp. 143 & 177) expresses doubts as to the 

 distinctness of Cenia Cocksii from Actaeonia corrugata. I would 

 hazard the suggestion that A. corrugata is but an immature stage of 

 Cenia Cocksii, with nascent tentacles. In any case, I am satisfied 

 that most of my Co. Dublin records for A. corrugata (Ir. Mat., 1908, 

 pp. 112 ; 1909, pp. 169 & 174) should be referred to the present species, 

 A. Cocksii, which is new to our Irish fauna, though not an addition to it 

 if it be really identical with the already recorded A. corrugata. 



Sub-Order Nudibranchiata. 



Aeolis papillosa (Linne). W. E. Frequent : two specimens at low water, 

 Portarriv, Clare Island, July, 1910: 10 specimens, many ipawning, at 

 low water, Inishshimmel, May 10th, 1910. 



A. glauca Aid. and Hanc. "W. Rare : one specimen trawled by the " Helga" 

 in the bay in from 13-16 f., May, 1909 (G. P. Farran). 



