So 



HARD WICKE'S S CIENCE- G OS SI P. 



Sandsfoot Castle, the algologist, if he be fortunate 

 enough to be there at a low springtide, will find the 

 Zostera beds uncovered, and among them may gather 

 the "mennaid's hair" — Lyngbya majiiscula — forming 

 blackish patches on the sandy mud, and PoIysipJwnia 

 sitbiilifcra, a very rare species, of a reddish colour 

 when fresh, but black when dry, growing entangled 

 among the roots of the Zostera. Fringing the sides 

 of the pools he will find Laiircitcia tciiitissima, of a 

 pale yellowish colour in the water, but purplish when 

 dry, and Mesogloia Zostera in abundance, while in 

 deeper water and attached to Rytiphlcea, the singular 

 sausage-like fronds of Aspcr-ococcns Tiirncri at once 

 attract attention. In the shallower pools the pretty 

 Padina pavonia occurs in some abundance, while 

 Stilop/iora rJiizodcs, and a narrow form of Ciitlcria 

 vntltifida, only distinguishable from the last by its 

 ilat fronds, are cast up from deeper water. 



E. M. Holmes. 



WATER SNAILS ; A STUDY IN POND LIFE. 

 Bv THE Author of " Plant Life." 



AND so you think we have entirely explored the 

 whole of this quiet Surrey village and its 

 beautiful surroundings of hills and valleys, woods and 

 shady lanes ? You are mistaken, my friend. There 

 is sufficient ground unbroken to afford us yet a score 

 of rambles ere we return to town. This afternoon I 

 want to take you for a stroll along a lovely lane, where 

 we can walk in the grateful shade of smooth-stemmed 

 giant beeches. Anon, the path lies over the slope of 

 a hiU, between banks of sandstone, where we may 

 gather ferns galore, and harebells in profusion. 

 Again it dips, and we pass through a copse. Further, 

 a bit of boggy ground attracts our attention to swarms 

 of the round-leaved sundew, whose dainty crimson 

 rosette-like leaves show brightly amidst the tufts of 

 fresh green sphagnum. On again, and soon we 

 have to push our way through bracken more than six 

 feet high, coming out upon a bit of heathy ground 

 with a farmhouse to the right. Just past the farm- 

 house is another lane with male ferns thickly clustered 

 in the hedgebanks. To the left there is a gap in the 

 bank, and we pass through into a wilderness of gorse 

 and bramble. Near us is a large pool, sheltered by a 

 tree or two, about whose far-reaching roots scores of 

 the stiff pale fronds of the prickly-toothed shield- 

 fern rise up. Let us throw ourselves beneath this 

 tree and see what there is to be seen. There is ex- 

 citement caused by our approach. Splash ! splash ! 

 Avhirr ! caused respectively by a big frog, a vole, and 

 a moorhen ; the two former taking shelter in the 

 pond, the latter fluttering through the bushes away 

 from it. All now is quiet — still as death, and not a 

 ripple on the surface of the tarn. Over the water flit 

 many dragon-flies in search of insects smaller than 

 jhemselves. There are three well-defined varieties 



we can distinguish on the wing. One, a tiny, fragile 

 bright blue insect whose rapid, but apparently 

 motionless flight, is attained by the ceaseless flutter 

 of its delicate wings. Then a larger, robust-looking 

 species, with long, broad wings, and a short, broad, 

 and depressed body, coloured grey-blue, and lacking 

 the fine polish ef the third species, which is the 

 dragon-fly, par excellence. This third kind, which 

 may represent several species, has grand netted wings 

 which measure four inches from tip to tip. Its 

 body is round, and richly marked with stripes and 

 bands of yellow, blue, and green. Its beautiful 

 luminous eyes are very large, and occupy a consider- 

 able portion of the head and face. All the species 



Fig. 52. — Lytn- 

 7ica pej'cger. 



Fig. 51. — Pond Snail ^Zywzw^rt siag}ialisj. 



Fig. 53.— Shell of Lymnea niiriciilaria. 



love to linger near the pools, where their early lives 

 were passed, darting over the water in pursuit of 

 more defenceless creatures. 



The water's surface is partly covered by the tripar- 

 tite leaves and the beautiful woolly-throated, softly- 

 tinted flowers of the bog buckbean, whilst below there 

 is an aquatic jungle of pond-weed, through which, 

 great shoals of the three-spined stickleback come into 

 the clearer water, returning rapidly on the slightest 

 suspicion of danger. Let us take our net and draw it 

 rapidly through that miniature forest. The mimic 

 trees bend to the slight force exerted, and much of 

 their animal life is dislodged. We bring the net 

 (constructed of stout holland with a piece of strong 



