nr, 



HARDWICKE'S SCIEN CE -GO S S IP. 



meut obtaiued from Mr. Colinau's artesian well, at 

 Carrow, Norwich. 



The following extract from a paper ou the process 

 of silicifieation of animals, read before the Geolo- 

 gical Association last year, by Mr. H. M. Johnson, 

 E.G.S., may perhaps be of interest. The author 

 points out "how a crop of sponges invested with* 

 their gelatinous flesh or sarcode, and living at the 

 bottom of a deep ocean, were suddenly buried in a 

 thick stratum of white mud, consisting of the minute 

 shells of foraminifera ; that they then died, and that 

 while in the process of decomposition this inter- 

 change of materials took place ; the nascent carbonic 

 acid parting with its carbon in exchange for the 

 silica of the silicate of soda which sea-water is 

 known to contain." 



To illustrate the power possessed by decomposing 

 organic matter he produced two tadpoles, or rather 

 one and the remains of a second. The first had 

 been placed in a solution of silica, and after the 

 lapse of a few hours was submitted to the action of 

 nitric acid, without any apparent injury : the other, 

 ■which had not been submitted to the silicifyiug 

 process before being placed in the nitric acid, was 

 instantly destroyed, the only trace of it being a 

 little brown cloud floating in the acid. 



The discoveries made in the dredging expeditions 

 of the Porcupine and the Noma have given an im- 

 petus to the study of the sponge forms, and although 

 we may not have the opportunity of adding new 

 genera or species, all of us who possess a micro- 

 scope can study the life history of the common 

 fresh-water sponge, Spongilla fluviatilis. It may be 

 found in almost every pond or small stream, and a 

 few hours' study of a fragment of a living sponge 

 will give the observer a better idea of that mar- 

 vellous substance we call sarcode or protoplasm, 

 than any lecture or paper can ever hope to do. — 

 Tratts. Norfolk and Norwich Naturalists' Soc, 1872. 



I^OTES ON NATURAL HISTORY IN THE 

 NEIGHBOURHOOD OF ROTTERDAM 

 AND GHENT. 



THE STORK.-I saw nothing of this bird in 

 Rotterdam itself; perhaps the place was too 

 busy for it. At Delfshaven, a village near the town, 

 a party of storks had taken up their abode. There 

 were seven of them ; I think they were the two 

 old birds and five young ones. The nest was on a 

 low brick chimney, right in the village ; the nest 

 was much larger than the chimney, and j projected 

 all round. When I first saw them, on the 15 Ih of 

 July, they were all full-grown ; they hovered and 

 wheeled about at a great height in the air, as if 

 practising for their departure southward, which 

 took place about the end of the month. The birds 

 seemed very tame, and swooped down between the 



houses quite fearlessly. Their resting-place was 

 the ridge of the church roof, where they stood on 

 one leg, in the sun, cleaning their feathers. In the 

 fish-market at the Hague there were some tame 

 storks that fed on the refuse from the fish. They 

 did not seem in very good condition ; perhaps the 

 fact of their not migrating did not agree with them. 

 Rude figures of this bird constantly occur in bits 

 of wood carving over doorways, &c.,or cut in stone on 

 the houses in Rotterdam, while nearly all the country 

 cottages have a curious sort of iron dome-shaped 

 frame over their chimneys, which are supposed to 

 induce the storks to build. The latter are believed 

 to bring good luck with them. The Heron, as would 

 be expected, was very plentiful, both in Holland 

 and Belgium, and birds in general were very abun- 

 dant about Rotterdam ; quite different from France 

 in this respect. I was told by a naturalist that 

 plovers differed slightly in plumage from English 

 ones. 



Amongst the fresh-water Molli/sca, the Umonidte 

 hold an important place. The commonest species 

 about Rotterdam was Unio pictorim. The shells 

 were longer and thinner than my Thames speci- 

 mens. I noticed quantities of rotten shells of 

 this species and Anodonta cygnea, in the sandy 

 loam that had been cut for a new canal. There 

 were also large tree-trunks lying in the soil, which 

 is quite destitute of stones. In a heap of gravel, 

 which, I was told, had been brought down from the 

 Rhine, there were a number of JJnio littoralis. I 

 had never met with it in a living state before, 

 although it occurred in a fossil state, associated 

 with recent land and fresh-water shells, Cijrena 

 fluminalis, and elephant remains, at Erith, where I 

 got fossil specimens. Anodonta cygnea was com- 

 mon enough, but I did not see any large specimens ; 

 those from the canal at the Hague were small, 

 ventricose, and ill-formed ; perhaps the sandy bottom 

 in most of the canals is unfavourable to the species. 

 Dreisseua pohjmorplia was very plentiful in the 

 river Maas. About Rotterdam the water is quite 

 fresh, although rising and falling with the tide. 

 The sandy soil on which the town is built is full of 

 dead shells in places, of fresh-water species, B. 

 polymorpha amongst them. 



The sea mussel {Mytilus edulis) is very much 

 eaten in Holland and Belgium. In Ghent it was 

 served up as a delicacy at dinner. In the museum 

 there is a picture by Albert Cujp, at Rotterdam, 

 of a blacksmith leaving his forge to come out and 

 eat mussels, with a group round him, just such as 

 you see in the back part of Rotterdam at present 

 round a mussel-cart. 



The Goat-moth (Cosstis ligniperda) infested the 

 endless rows of pollard willows along the roads and 

 dykes. The perfect insect was over ; but there 

 were lots of empty pupa-cases sticking out. One 

 of these moth-infected trees was the centre of 



