MARINE MOLLUSCA OF DONEGAL AND DUBLIN. 51 



(3) There is one specimen, having all the appearance of such 

 a cross, in the Cambridge University Museum, and this specimen 

 is believed by Prof. Newton to be a genuine example. 



(4) The fact, however, that this bird was the only one in the 

 covey so marked, together with the extreme variability of Red 

 Grouse, the frequency among them of albinistic varieties, and 

 their close relationship with the Ptarmigan (L. mutus) making it 

 probable that they would throw back on a common ancestor, and 

 the, in any case, extreme rarity of such a cross, all tend to cast 

 doubt on the hybrid origin of the Kintradwell bird now preserved 

 at Cambridge. 



(5) There is no apparent reason why such a cross should not 

 occur in nature ; on the contrary, it is rather surprising that it 

 has not occurred and been identified more than once. 



My answer, then, to the question — Has the Red Grouse 

 (L. scoticus) been known to interbreed with the Ptarmigan 

 (L. mutus) ? — is, that I know of no unimpeachable record of such 

 a hybrid, and of only one probable example. 



NOTES ON MARINE MOLLUSCA COLLECTED ON THE 

 COASTS OF DONEGAL AND DUBLIN. 



By H. Chichester Hart, F.L.S. 



1 venture to offer the following list of Irish Mollusca, being 

 the result of my collections along various beaches from the years 

 1881 to 1887. A little dredging and trawling experiences will 

 be found interspersed. I am aware that gathering shells along 

 the shore is not the most scientific method of studying Marine 

 Conchology, nor is it even a useful plan for forming a 

 collection, as the specimens are commonly unfit for the cabinet, 

 though I have, of course, preserved what I gathered ; but a valuable 

 insight into the life of the adjoining sea is at any rate obtained in 

 this way, and in a comparatively brief period of search. The 

 dredge and the trawl will frequently descend and ascend without 

 bringing up a single shell, but if the strand be properly selected 

 a day's search may easily yield close on a hundred varieties, often 

 battered, but almost always identifiable. Moreover, dredging is 

 only rarely practicable on such stony coasts as those of Donegal, 

 and always both expensive and troublesome* I feel therefore that 



