438 THB MICROSCOPE. 



gular class of objects are Diatoma ftocculosum, beiig rather 

 oblong-looking, and joined -to each other at opposite cor- 

 ners : they are sometimes grooved on each side. (Fig. 225, 

 No. 17.) The "Swollen Eunotia" is generally about 

 from the llth to the 200th of an inch in length: a 

 groove, widest in the centre, and tapering off to the ends, 

 passes along its centre on both sides ; it has curved lines 

 proceeding from it. So wonderfully close are these lines 

 or ribs, that as many as eight of them havt* been 

 counted in the space of the ] 200th of an inch. They are 

 usually found when alive adhering to a branch of some 

 weed that forms the green coating over stagnant waters. 

 They propagate by self-division ; a slight line running 

 down the centre marks where the separation will occur, 

 on each becoming perfectly developed as a distinct crea- 

 ture ; and thus they grow and separate, filling the earth 

 with their flinty shells. 



Gallionella sulcata is found m many parts of North 

 America ; it somewhat resembles the cylindrical box for 

 spices, which was at one time so common among good 

 housewives; scientifically, it is described as consisting of 

 chains of cylindrical bivalve loricee, having their outer 

 surfaces marked or furrowed with longitudinal striae ; short 

 joints may occasionally be seen, having their ends upper- 

 most, the depth of the furrows being shown on the margin; 

 within the margin is a thin transparent rim having ra- 

 diating striae. Sometimes as many as forty will be found 

 joined together. (Fig. 225, No. 9.) The Gallionella received 

 its designation from a celebrated French naturalist named 

 Gaillon, it is often termed the Box-chain Animalcule, and 

 when the flinty case is seen lying on its face, it much re- 

 sembles a coin. These living infusoria are found in almost 

 all waters, and are stated to be so rapid in their growth, 

 that one hundred and forty millions will by self-division 

 be produced in twenty-four hours. A species named the 

 Striped Gallionella was discovered by Dr. Mantell near 

 London ; the same species is also found in the ocean. 

 Sometimes the chains are three inches long; their size is 

 from the 14th to the 400th part of an inch. 



Professor Quekett, in the catalogue already referred tcs 

 describes an " earth from Bohemia, particularly rich ID 



