NATURAL HISTORY SOCIETY OF GLASGOW. 231 



exposed for a few days, while the normal form bears an efflorescence 

 of saline compounds, chiefly salts of potash and soda. Besides, 

 while the frond only of the latter is annual, and cast off every 

 spring, this variety becomes detached a short way down the stem, 

 and thus the whole frond, with part of the stem attached, is thrown 

 on shore in May when the plant is ripe. Mr Mahony also exhiljited 

 illustrative specimens of L. digitata and the variety stenojjhylla. 



PAPERS READ. 



I, — ])[otes on a Botanical Tour, with Mr W. Gait, to Ben Lawers. 

 By Dr James Stirton. 



In the course of his remarks, Dr Stirton exhibited a collection 

 of rare mosses, chiefly of the genus Hypnum, ten of which had 

 hitherto been found in this country only on Ben Lawers. Among 

 these were two species new to Britain — Brachythecium Starkii 

 and Hyjmum Bamberger i— the latter having been found in 1867, 

 in the same locality, by Dr Fraser, Wolverhampton, and one new 

 to science — Plagiothecium annotinum. Besides these, Hypnum 

 imponens, new to Scotland, was also found. 



II. — Notes on Bytiscus Lapponicus (Gyllenhal) collected in Ireland 

 during the present Autumn. By Mr Jaivies E. Somerville, B.D. 

 All who, with naturalist's eye, have stooped and peered into 

 njarsh or quarry hole, ditch or pool, must be familiar with the 

 large water beetle Bytiscus marglnalis; for though in Scotland he 

 is less abundant than in the southern portion of the island, yet he 

 is plentiful enough to have found a place, for a time at least, in 

 all our fresh water aquaria. And surely none can there have 

 observed the graceful lines of his build, the wonderful structure 

 of liis patent floats, with their regular and simultaneous action, 

 the curious arrangement of the windsail or ventilating apparatus, 

 the strange anchoring appliances on the fore limbs of the males, 

 without being forced to admire the wisdom and skill of the Archi- 

 tect and Builder of this little living ship, and its remarkable 

 adaptation to the element it is intended to navigate But in spite 

 of all these points of attraction, B. marginalis is generally soon 

 expelled the aquarium. The newts succumb to his voracity, and 

 even the minnows find Ids powerful jaws the plague of their 

 lives. 



B. marginalis may be taken as a good type of the genus, of which 



