11)8 DESCRIPTION OF [Polygastrica. 



diameter varied from 1 -240th 1-1 150th of an inch. He 

 considers it very probable that they belonged to the 

 siliceous Infusoria, as siliceous spiculi belonging to the 

 genera Spongilla, Xanthidium, and Pendinium, were met 

 with in the same situation ; whether they should be placed 

 in the genus Pyxidicula is doubtful, as no furrow or 

 division was observed on the shell. 



209. PYXIDICULA operculata. The box-like Pyxidicula 

 is shewn at group 127- The lorica is transparent and 

 spherical ; it contains yellowish-green ova-like matter. The 

 upper figure is a view at right angles to that drawn on the 

 left, shewing the furrow by which it separates ; and the figure 

 to the right is a hemisphere thus detached ; in the lower 

 figure a transparent glandular body is observable. No 

 locomotion has been seen. I have found them abundant 

 in autumn, among Navicula, at Hampstead. Diameter 

 l-1440th to l-570th. 



210. PYXIDICULA globator. The ball Pyxidicula. I 

 insert under this name the globular bodies found in the 

 flints, as mentioned in the concluding remarks on the 

 genus. The section of pebble containing the specimens 

 from which Mr. Bauer's drawings in plate xii., fig. 506 to 

 510 were taken, was found on the Brighton beach ; they 

 are represented magnified 100 diameters. 



Genus LVI. GALLIONELLA. Tfie box-chain Animal- 

 cules are characterized as free, and possessing a simple 

 bivalved siliceous lorica, of a cylindrical, globular, or discoid 

 form. In consequence of an imperfect longitudinal self- 

 division, they develope themselves in the form of a chain. 

 The single members have one or two oblique furrows, with 

 several openings in them. The lorica, when lying on its 



