192 PROCEEDINGS OF THE 



Tlie Pisidki need not engage our attention much, excejit it be 

 to reflect how every Httle bit of marsh and stagnant pool becomes 

 so ra})idly and so numerously filled with them. The specimens 

 in tlie collection are from the vicinity of Torrance, and were found 

 in a small hollow which had every appearance of being caused by 

 the subsidence of the old workings of a coal pit, which had got 

 filled with rain water. By pulling up the grass they will be found 

 adhering to its roots. 



Drcissena j^oh/morpha, from Lambhill Bridge eastward, on the 

 towing side of the Forth and Clyde Canal, adhering to the stones, 

 about a foot below the surface of the water, very plentiful and 

 easily procured. 



Bythynia tentaculata. — Anywhere on the Forth and Clyde or 

 Paisley Canals, on stones and aquatic plants. 



Val'vata piscinalis. — Inshot on Paisley Canal, a short distance 

 east of second bridge. I also found it in an old lade at Dalmuir, 

 where the glacial shell bed crops out, forming,. along with Ci/rlas 

 cornea, the larval case of the May fly. Falvnta cristata. — "The 

 Splash," on Forth and Clyde Canal, and at Springbank, on roots 

 of plants. 



Pla7iorbis nitidus. — Same as last. Planorhis alhus. — Very plentiful 

 in the drain running from Frankfield to Hogganfield Loch; and 

 in Bishop and Johnstone Lochs, Gartcosh, on j^lants. Flanorhis 

 spiwrhis. — Small marsh on Eutherglen Road; very plentiful in 

 Bishop Loch, on plants. Planorhis contortus.- — Numerous in Frank- 

 field Loch, on plants. 



Physa fontinalis. — Very common anywhere in the canals or 

 stagnant water, on plants and stones. 



Limnma peregra. — ^Same as Physa, but more often found on 

 stones and on the bottom at the maririn of the water. The larce 

 specimens in the collection I found in a deep and sheltered 

 pond in which there is a slow current, and which is the principal 

 feeder of the npper reservoir of the Gorbals Gravitation Water 

 Works, all of them Avere adhering to stones quite near the side. 

 L. auricularia. — Noi-thern bank of the Monkland Canal, on the 

 ground in shallow water close to the side, at the western ex- 

 tremity of the first plot of sedges going east between the third 

 and fourth bridge, counting the bridge crossed by the Cumber- 

 nauld Road the first. L. trnncatula.— Very plentiful on the mud 

 at the margin of Clyde, Dalmuir, and in such situations; this 



