132 



HARDWICKE'S SCIENCE-GOSSIP. 



Aralo-Caspian fauna (cp. Forbes and Hanley in 

 "British Mollusca," F. T. Koppen and Nehring 

 "SB. Nat. Fr." 1883, pp. 68, 69), whence they 

 have migrated northward by the Volga and its Oka 

 confluent. Their " march " across Europe has been 

 noted among others by Noll, Maudel, and Greim 

 (" Zoolog. Gart. Frankf." 1864, pp. 30, 89 and 124), 

 Kreglinger (" Verh. ntrw. Verein Karlsr." vol. I), 

 Merian (" Vehr. ntrf. Ges. Bassel," iv. 1S64, p. 94), 

 Morlet (" Journ. de Conch." pp. 309-314, I believe 

 in 1864 or 1866 volume), Von Martens ("Zool. 

 Rec." 1S64), Mabille ("Journ. de Conch." xv. pp. 

 108-110), P. Fischer ("Journ. de Conch." xv. pp. 

 , IIO-lii), Dranitz (" Wurtemberg. naturwiss. Jahres- 

 hefte." xxiv. p. 44), Gassies ("Journ. de Conch." 

 xvi. pp. 17-24), Krauss (Jahresh. ver. vaterland. 

 Naturk. Wurth xxiv. p. 44), Martens ("Mai. Blatt." 

 xvi. p. 84), and Siebert (Nachrichts. mal. Gesellsch. 

 I. p. 101). That it was an inhabitant of the old 

 Aralo-Caspian fauna is further enhanced by the fact 

 that Helmersen ("Bull. Ac. Sc. St. Petersburg," 

 1868, pp. 23-25), has found it extinct north of the 

 Syrdarja river, in the desert of Kara-Kum, which still 

 further proves, as he says, that Lake Aral had a 

 much greater extent in remote times than it has at 

 present. 



J. W. Williams. 



N.B. — Since writing the above, I have noticed that 

 several specimens have been placed in the National 

 Collection under its name of H. Jenkinsi. This 

 I regard, under the circumstances, as decidedly 

 premature. — J. W. W. 



HOW DEEP DO HIBERNATING 

 MOLLUSCS BURROW? 



COMPARATIVELY few conchologists, I observe, 

 think it worth while going on their inoffensive 

 war-path in the winter, when their prey is buried 

 torpid in the mud, deep among the roots of trees, or 

 among the foundation stones of walls. Of course, 

 during open weather most land shells are to be found 

 in their usual habitats all through the winter, but I 

 should like to draw attention to the periods when the 

 weather is not open. 



Some years ago I made an excursion to the Isle of 

 Man at Christmas time for a fortnight's collecting. 

 All went well for a few days, snails and slugs being 

 almost as numerous as in summer. Then a bitter 

 east wind sprang up one day as I started on a hunt 

 over the Curragh. I had provided myself with a pair 

 of long sea-boots, a sou'wester, a pair of thick gloves, 

 and provisions. I spent the whole day wading 

 through water, which was trying to freeze, scooping 

 vigorously and not unsuccessfully. The gloves were 

 the most troublesome part of the performance, as 

 they continually got wet, so that I had to keep taking 

 them off to put them to dry inside my waistcoat, 



while I warmed my hands with my pipe. The next 

 day all the swamps were frozen over, so I left the 

 Curragh and went to Port Erin to visit the stone 

 walls. Many of these walls, made of turf and stones, 

 had been very productive on former occasions, but 

 now they were frozen hard. I thought it, however, a 

 good opportunity to see how far snails burrowed 

 during frost ; and to that end, by means of a rock, I 

 broke down a considerable part of some walls, which 

 did not seem to be of any particular use, for which I 

 hope the owners have now forgotten and forgiven, 

 especially as I got very little for my pains. I then 

 went into some small woods and dug among the roots 

 of trees, where I was rather more successful. The 

 snow came the next day, covering up my depreda- 

 tions and putting an end to the work on the land. I 

 then turned my attention to the sea and spent a 

 pleasant, though somewhat cold time among the rock 

 pools at low tides, till at last these pools began to 

 freeze, and I had to confess myself beaten. 



I own that such an experience does not altogether 

 tend to induce others to do likewise, though it was in 

 fact most enjoyable. My failure with the walls made 

 me consider the question as to how deep the snails go 

 during frost. I had excavated fairly deep and had 

 found hardly any at all. This question has puzzled 

 me ever since, and my object in writing this is to 

 elicit the answer from some one who has been more 

 fortunate or more persevering than myself. 



During this last, or rather present winter I have 

 been experimenting to the same end, choosing some 

 uncultivated spots in the limestone district of Derby- 

 shire, (where my excavations could do no harm, 

 being still filled with remorse for my many depreda- 

 tions), in the corners of fields, where heaps of stones 

 overgrown with moss and nettles, and abounding in 

 empty shells of H. arbustorum and H. nemoralis 

 showed that in summer molluscan life was plentiful. 

 I removed, I suppose, fifteen or twenty such heaps, 

 and found only an occasional adult hibernating, 

 young specimen being far more common perhaps, not 

 having the strength or experience to secure safer 

 quarters. The stones cleared away, I proceeded to 

 dig a foot, sometimes a yard into the soil, and even 

 then found very few, often none at all. This was in 

 open weather after frost. 



Now and then I have found an individual, usually 

 an adult, content to hibernate at the bottom of a wall 

 or stone, quite uncovered. Had he been overtaken 

 suddenly by the cold and obliged to secrete his 

 epiphragm forthwith, or did he deliberately choose that 

 spot in defiance of the cold ? In the south of England 

 I have often found H. aspersa massed in crowds 

 under bricks, potsherds, slates, etc., on the surface oj 

 the ground, never below it, except in crevices ; but 

 whether that species is hardier than others, or 

 whether instinct has told it that the winter would not 

 be severe, I cannot say. That its size alone does not 

 interfere with burrowing H. pomatia proves, nor is its 



