200 DESCRIPTION OF [Polygastrica. 



polishing silver-plate. Found near the Upper Bann, 

 Ireland. Size l-2200th to l-480th. 



214. Gallionella moniliformis. The bead-like Gal- 

 lionella is cylindrical, short ; ends truncated cones ; when 

 single and viewed from the back, they appear octagonal. 

 The lorica is smooth, and the ova of a greenish colour. 

 Found in sea- water, and often confounded with G. lineata. 

 Size l-860th. 



215. Gallionella aurichalcea. The golden Gal- 

 lionella is cylindrical, the length full twice the diameter. 

 It has either a single or two perforated rays contiguous 

 at the middle ; the ova are green, but when dried become 

 of a golden-yellow colour. Thickness of chain 1 -2300th 

 to 1-1 720th. 



216. Gallionella ferruginea. The rust-like Gallio- 

 nella has a slender oval lorica, convex at both ends ; 

 surface smooth. They are developed in the form of 

 articulated threads, often agglutinated together, as if 

 branched. In many, perhaps in all, chalybeate waters, 

 and also in peat water, which contains a small proportion 

 of iron, this curious little animalcule is to be found ; it 

 is of the colour of iron-rust, and in mineral springs in 

 which it abounds is often taken for precipitated oxide of 

 iron. It covers every thing under water, but forms so 

 delicate and floccose a mass, that the least motion dissi- 

 pates it. In the spring of the year, this mass is composed 

 of very delicate pale yellow globules, which can be easily 

 separated from each other. In their native abode they 

 hang together in rows, like short chains, and produce an 

 irregular gelatinous felt or floccose substance. About 

 summer, or in autumn, they become developed into more 



