VOKTICELLID^E. 163 



exactly similar respectively to one another." See Microscopical Society's 

 Transactions for an excellent paper on these shells by Mr. Shadbolt. 



Man even uses infusorial remains as food ; for the berg-mehl, or moun- 

 tain-meal (represented in fig. 95, No. 8), found in Swedish Lapland, 

 and which, in periods of scarcity, the poor are driven to mix with 

 their flour, is principally composed of the flinty shells of the Gallionella 

 sulcata, Navicula viridis, and GompJwnema gemminatum. Dr. Trail, 

 on analysing it, found it to consist of 22 per cent of organic matter, 72 

 of silica, 5-85 of alumina, and 0'15 of oxide of iron. This would seem to 

 be the same substance described by M. Laribe the missionary, and put 

 to a similar use in China : " This earth," he says, ' is only used in sea- 

 sons of extreme dearth. One of our Christians, who, at the period of the 

 last famine, fed upon this substance, with five other individuals com- 

 posing his family, informed me, when they made use of it, they bruised 

 it into a very fine powder, mixing three parts with two of rice-powder, 

 or, better, the flour of wheat, to make small eakes, which were seasoned 

 with salt or sugar. Kecourse was only had to this in times of great 

 want ; and this being over, no one ever dreamt of making use of it as 

 an article of food. Those accustomed to partake of it complained of a 

 weight at the stomach and constipation. They could subsist for two 

 months on this material formed into cakes ; whilst without its assist- 

 ance, their provisions would only suffice as food for one month. Those 

 persons who employed the fossil-flour without mixing it with vegetable 

 meal, scarcely ever escaped disease." 



VORTICELLIDJ2. 



We now come to a family which includes some of the most beauti- 

 ful of the infusorial animalcules, and in which we meet with phenomena 

 more curious than any we have yet witnessed, and perhaps as wonderful 

 as any that will be presented to our notice, when studying the natural 

 history of the higher classes of animals. This is the family of the Vor- 

 ticellidce, or bell-animalcules. The animals of which it is composed are 

 characterised by the possession of a fringe of rather long cilia, surround- 

 ing the anterior extremity, which can be exerted and drawn in at the 

 pleasure of the creature. Some are furnished with a horny case for 

 the protection of their delicate bodies, whilst others are quite naked. 



The genus Vorticella, from which the name given to the family is 

 derived, consists of little creatures placed at the top of a long flexible 

 stalk, the other extremity of which is attached to some object, such as 

 the stem or leaves of an aquatic plant. This stem, slender as it is, is 



