FOSSIL INFUSORIA. 



437 



lanceolate shape, and a little indented on both margins ; 

 two of them have curved rows of dots, and the other two 

 are partly grooved with finer rows. Ehrenbeig says they 

 have four openings, all on one side (fig. 225, No. 13), 



7, Cnmpilodiscus cli/per/3. 8, Biddv.lyhia. 9, Gallionelia sulcata. \0, Trice- 

 ratium, found in Thames mud. 1 1, Gomphonema geminatum, with their s-talk- 

 like attachments. \2, Dictyocha fibula. \3, Eunotia. \i, Cocconema. 15, Fra- 

 gilariapeitinalis. 16, Meridian circulnre. 17, Biatoma fli-cculosum. 



presenting a row of dots varying very much in number ; 

 minute striae in some cases extend from each dot towards 

 the middle of the lorica ; and on the circumference there 

 are two of these dots. The spirals and the individual 

 lorica are very fragile, and therefore easily separated from 

 each other. Of a glistening whitejiess is the ribbon-liko 

 flinty case of Fragilaria pecii/icdis, whicli consists of 

 many bivalve segments : on the articnlating surface tbero 

 are small grooves, represecied in fig. 225, No. 15. A siu- 



