Baciilaria.] THE infusoria. 215 



269. EuNOTi A joew^orfow, five dentations. Length l-570th. 

 Fossil, at Bergmehl. 



270. EuNOTiA diadema, six dentations. Length l-238th. 



(Finland.) 



271. EuNOTiA serra, twelve or thirteen dentations. 

 Length l-280th. (Sweden.) 



Genus LX. CoccoNEis. — The shield little ship Animal- 

 cules. — These Baciilaria are free, their siliceous lorica is 

 bivalve and prismatical, or somewhat hemispherical in 

 shape, with two apertures, one in the middle of each 

 piece. They are never developed in the form of a chain, 

 and their propagation by self- division, or gemmules, is 

 doubtful. They never cluster, and are mostly striated ; 

 the transverse striae appear to be internal flutings like 

 ribs. The lorica is composed of two lateral pieces, joined 

 together at a central furrow, somewhat resembling the keel 

 of a boat, the under surface being flat, the upper some- 

 what arched. A foot-like process has been seen projecting 

 out of the central opening, on the under surface. The 

 internal matter, or ova, is green or yellow, and often 

 appears to be formed in two plate-like masses. Though 

 the actual motion has not been observed, change of place 

 appears to ensue. 



272. CoccoNEis scutellum The shield Cocconeis has a 

 convex elliptical lorica, externally granulated, with trans- 

 verse striae internally. They are found upon the sea-weed 

 Ceramium diaphanum, a portion of which, with their 

 Infusoria, is shewn at group 162, and a single specimen 

 at fig. 163. Fossil in the Schist (Polirschiefer) of Cassel. 

 Length 1-11 50th to 1 -240th. 



273. Cocconeis midulata. The wave Cocconeis has the 



