iyi4 Stklfox. — Molhisca of Cotinty Derry. 131 
Limnaea palustris, Miill. — Fine specimens in the marsh by Tamniarm 
Biitljje, wliich crosses the Roe two miles above Dungiven. In ponds 
near .Ma^iUigan Point (Welch, 1896. Also Milne). NNN. 
L. truncatula, Miill. — Frequent, to 600 feet on Keady Mountain. NNN. 
Pianorbis crista, L. — Formerly common in the pond by the railway at 
Limavady Junction (Milne) ; but none were seen by me in this spot 
in June, 1909, though Mr. Welch took a few here in 1904. 
P. leucostoma, Millet ( = P. spirotbis, Auct.) — In drains by the railway at 
Limavady Junction ; in the marsh below Dungiven Abbey ; and in 
drains on the Magilligan fiat. NNN. 
Some years ago specimens of this species, P. /(?/rco5/o;«r/ Mill., collected 
by me on Gorteen Point, Dog's Bay, West Galway, were named by the 
late Dr. Boettger " true Pianorbis spirovbis of Linnc." As, however, I 
was able to connect these shells with typical P. leucostoma by specimens 
of intermediate form, I came to the conclusion that we had only one 
species in Ireland, and that, though very variable in form, all our specimens 
belonged to the P. spirorbis of Linue. Since that time I have seen con- 
tinental examples of the supposed true P. spirorbis, which appear to differ 
specifically from our common Irish shell. Moreover, I have taken a 
Pianorbis in the marsh at Ballyphehane, near Cork — Mid Cork — which 
agree with these continental specimens, and between which and P. 
leucostoma I have been unable to find intermediates. I am now, therefore, 
inclined to consider that the P. spirorbis of British authors must be split 
into two, viz., Pianorbis spirorbis of Linne and Pianorbis leucostoma of 
Millet. Mr. A. S. Kennard, F.G.S., of London, adopted these two 
species some time ago, and it is thanks to his help that I have arrived at 
the above conclusion. Besides those from Cork, I have a single example 
of the true P. spirorbis from the canal near Shalford, in Surrey, which 
was taken within a few yards of a marsh in which P. leucostoma was 
abundant. Although I believe the two species are distinct, they closely 
resemble each other, and I have no doubt that many continental records 
for P. spirorbis should really be referred to a large -whorled form of P. 
leucostoma, since I have received from the continent more than one lot 
of the latter under the name of " P. spirorbis, Linne." 
P. contortus, L. — Occurs in the lakelet by the path leading up to Bene- 
venagh from Tamlaght Old Church, about 200 feet above sea -level. 
Also taken on Magilligan Point (Welch, 1896). NNN. 
Physa fontinalis, L. — In ponds on the Magilligan fiat (Milne, 1893). NNN. 
Aplecta hypnorum, L. — In marshes about Limavady Junction and 
Magilligan, but it appears very local. NNN. 
Paludestrina Jenkinsi, Smith. — Abounds in the drains about Limavady 
Junction, where it was first seen (Welch and Milne) in the year, 1904. 
In former years it was never seen there by Mr. Milne, though during 
the "nineties" he collected extensively in the district. NNN. 
P. stagnalis, Baster. — Common by the shore of Lough Foyle. NNN. 
Bithynia tentaculata, L. — In the ponds on the Magilligan fiat (Milne, 
1893). NNN. 
Valvata piscinalis, Miill. — Occurs in drains near Magilligan station. NNN. 
