I904- Notes. 29 



A. dilatatus (new species) ; A. crenatus^ Koenike (new to Britain) ; A, 

 tricuspidator, Muller ; A. claviger^ Koenike ; A. Bruzelii, Koenike ; A. 

 albator, Muller ; A. crassicaudatus, Kramer , A. Kaiiei, Halbt. ; A. siniiator, 

 Muller ; A. jorpicatiis, Neuman ; A. solidus, Piersig ; A. sciilptus (new 

 species) ; A. triincatellus, Muller. 



Most of these are widely distributed European species ; some, how 

 ever, are very rare, such as A. Kanei, which was dredged in Lough Erne 

 and elsewhere in Ulster. It is nearly related to a Scandinavian species — 

 A nobilis — described by Neuman many years ago from I^ake Malar. 



Decalcification of Freshwater Shells. 



While dredging some years ago for the Fauna and Flora Committee, 

 R.I.A., in the deep hole in Lough Neagh, south of Toome, I noticed in 

 all my hauls, in between about 80 to 96 feet, some curious-looking objects 

 like minute collapsed bladders. They were very numerous, translucent 

 pale brown in colour, and about one quarter of an inch in diameter. These 

 were most puzzling. It was evident they were not the outer cases of 

 fish eggs that had hatched out — they seemed too large for that. I 

 submitted them to various authorities, none of whom could connect 

 them with any likely source. In Maj^ this year Mr. J. Pearson and I 

 were dredging in Lough Neagh for the newly-established Biological 

 Laboratory at Larne, and on the margin of the deep rift, in about sixty 

 feet of water, some Valvata piscinalis qm^ Limncsa peregta came up. These 

 were placed in a deep, wide-mouthed bottle, and, on swirling round, 

 some specimens were noticed in which almost all the shell seemed 

 merely epidermis, with only a small portion of the calcareous part of 

 the shell remaining in the spire. Later, in the deep hole — 96 feet— we 

 obtained a few Bythinia teniacvlata, Valvata piscinalis, and abundance of 

 Sphcerhan cornenvi, of which the epidermis only remained, with a few in 

 which portion of the shell was present. "With these were many Mysis 

 rclicta. This, then, was the explanation of my old finds — they were 

 S. corneum, entirely decalcified by acid in the water. This deep hole is a 

 mass of fine black mud, a veritable graveyard of myriads of shells, &c., 

 which live in the neighbourhood, with much decaying vegetable matter 

 and it is evidently the carbonic acid set free from decaying animal and 

 vegetable life that has dissolved the lime of the shells, leaving the 

 epidermis intact. This, as it floats round in water in a bottle, keeps 

 the form of the shell perfectly, especially in the case of the univalves. 

 As the dredge disturbed the bottom mud, masses of bubbles ascended 

 to the surface, doubtless carbonic acid gas. This question, however, 

 we hope to settle definitely on a future visit, with some othei faunistic 

 questions connected with this extremely limited deep area of a lough 

 which is very shallow, indeed, when compared with its large size. 



R. WKI.CH. 

 Belfast. 



