Bacillaria.] THE INFUSORIA. 201 



evidently articulated and stiff threads, of a somewhat 

 larger diameter, but still form a complicated mass or 

 web, and either from adhering to each other, or to deli- 

 cate conferva, appear branched. In the young condition, 

 when examined under shallow magnifiers, they resemble 

 gelatine ; but with a power of 300 diameters, the flexible 

 granules are discoverable, and with dexterous manage- 

 ment, the little chains forming the felt or floccose web can 

 be made out. In summer, on the other hand, its struc- 

 ture can be observed much more easily and distinctly. 

 Early in spring, the colour is that of a pale yellow ochre ; 

 but in summer, it is of an intense rusty red. Plate ii., 

 figures 129 and 130 exhibit chains of these creatures 

 diiferently magnified. Found both recent and fossil. 

 Diameter 1-1 2000th. 



217. Gallionella distans. The divided Gallionella 

 has short cylindrical corpuscles, plane and truncated at 

 both sides. Two perforated striae, or furrows, are pre- 

 sent, which are distant from each other. Found both 

 living and fossil. Size of corpuscle 1-345 6th. 



218. Gallionella sulcata. The obliquely -striped 

 Gallionella has short cylindrical coriDuscles, which are 

 externally transversely sulcated, giving rise to a cellular 

 appearance. See group 131, plate iii. Found only in a 

 fossil state. Size 1-1 150th to l-860th. 



Genus LVII. Actinocyclus. The rayed-box Animal- 

 cides are free, possess a simple bivalved siliceous lorica, 

 have a cylind rical form, and their interior divided by 

 numerous ray-like divisions. The self-division is imper- 

 fect, and they are developed in the form of chains. The 

 genus contains two species, which are only met with 



