SCIENCE-GOSSIP. 



99 



alive than dead; too often modern biologists forget 

 that their own name means students of life, many 

 are mere" necrologists" or students of death. I 

 would like to see my readers combine the two and 

 to be accurate and thorough students of form and 

 structure in order to better appreciate the life of the 

 animals and their relation to their surroundings. 



The marine zoologist employs three distinct 

 methods of collecting his specimens, these are 

 shore-collecting, tow-netting and dredging. 



There is no place so barren that it will yield 

 nothing to the shore-collector, although some 

 localities are very much better than others. 

 Beyond a few molluscs, worms and echinoderms, 

 there is very little to be found alive on sandy 

 coasts, but these are good hunting-grounds for the 

 flotsam and jetsam of storms ; chalky coasts, too, 

 are not prolific. The best localities are coasts 

 with reefs of limestone or igneous and meta- 

 morphic rocks running into the sea. So that 

 before fixing on an unexplored locality it is well 

 to have a look at a geological map as well as a 

 detailed survey map, for the latter gives the 

 character of the coast with remarkable accuracy. 

 After a little experience you will soon learn the 

 sort of fauna you may expect to find on various 

 kinds of coast ; sample all, not omitting the 

 vicinity of drains. You will find that life is 

 not abundant where there is exposure to a tidal 

 scour, as, for example, in a narrow sound between 

 a rocky island and the mainland ; but in the 

 sheltered nooks of such a sound there will 

 frequently be found a remarkable abundance of 

 animal life. The reason for this is obvious, the 

 continual rush of water prevents the fry from 

 settling down, this they can do in the backwaters 

 and the extra flow of the tide carries with it more 

 numerous floating eggs and swimming larvae, and 

 the water is always well aerated. 



Shore-collecting can be and should be carried on 

 at all times of the year. It is very interesting to 

 watch the succession of forms that make their 

 appearance at different seasons, and this aspect of 

 marine zoology has not had sufficient attention paid 

 to it. I would like to suggest to some resident at 

 the sea-side to select a convenient spot which 

 supports a varied fauna, it may be only a yard 

 square, and to accurately determine all the forms 

 there found living ; only the smallest fragments of 

 fixed forms need be taken away for identification, 

 and none of the free-moving animals should be 

 removed. The whole spot and its inhabitants 

 should be carefully recorded in a note-book, and 

 once a month for a year, at least, a visit should be 

 paid and all alterations noted. So far as I am 

 aware this has never yet been done, and I am sure 

 it is worth the doing. 



Of course shore-collecting can only be carried on 

 at low-tide, and the lowest spring-tides are the best 



for the purpose. To those of you whose summer 

 vacation is limited I would advise a reference to the 

 almanack before arranging for a holiday, and so 

 timing your excursion that a spring-tide occurs a few 

 days after your arrival. You will require those few 

 days to make preparation, and to discover the most 

 suitable localities ; and when you have a low-tide 

 make the best possible use of it — don't be tempted 

 to loiter on ground which you can examine another 

 day. You will find you can do very little shortly 

 after the tide has turned, although just at the turn 

 of the tide is a very favourable time. 



Next month I shall have something to say about 

 tow-netting and dredging, with some hints how to 

 preserve specimens. 



THE EGG-LAYING OF HELIX 

 POM AT I A. 



"T^ORTY years ago Mr. E. J. Lowe communicated 

 to the Royal Society some observations on 

 the growth of land snails, in which he stated that 

 " most species bury themselves in the ground to 

 increase the dimensions of their shells. Helix 

 pomatia and many other shells (sic) retreat for that 

 purpose in summer, having their heads and the 

 mouths of their shells downwards." Although 

 this statement is quoted by Jeffreys (" Brit. 

 Conch."), and most subsequent writers, I have 

 for years doubted its correctness. On June gth, 

 however, I felt sure I was wrong when I saw 

 dozens of shells partially buried in the chalky 

 soil at Reigate. Closer investigation revealed the 

 fact that instead of burying themselves the snails 

 were excavating holes in which to deposit eggs. 

 A number were actually removed from above holes 

 which they had roofed in, all but a small central 

 aperture. Several of these chambers were opened 

 and the eggs removed and counted. The internal 

 space was equal to the circumference of the shell, 

 and the contained eggs varied from seventeen to 

 thirty-one in number. Probably it was the exca- 

 vation of these pits that Mr. Lowe mistook for the 

 commencement of aestivation. If the growth of 

 the shell took place in the manner suggested 

 should we not find a continuously smooth and 

 even surface interrupted only by annual ridges 

 (varices) ? To my mind the rapid succession of 

 the lines of growth is evidence that shell-increase 

 takes place whilst the snail is actively engaged 

 feeding above ground. 



What are the habits of the young pomatia ? With 

 most other species of snails the immature specimens 

 are at least equally in evidence with the mature, 

 but one rarely meets with pomatia until it is 

 apparently four or five years old. The inference 

 is that it "lies low" among the dense herbage 

 until it has reached a mature age. 



Edward Step. 

 The Mays, Epsom ; June iSth, 1894. 



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