16 MICROSCOPICAL OBJECTS FOUND 



Many highly interesting examples of this group 

 occur in the Levant Deposit. The most striking 

 is the Denticella tridens, Ehr. — the Zygoceros 

 Tuomeyi of Bailey, (fig. 1.) The figure represents 

 two of the frustules, many of which have probably 

 been joined together, forming an elongated 

 filament. The same species has been found by 

 Dr. Bailey in the siliceous infusorial marls of 

 Piscatoway and Petersburgh, North America. 



Biddulphia pulchella (fig. 2.) is another beau- 

 tiful form belonging to the same group. Two 

 frustules are also represented. It is found on 

 our own coasts. Dr. Ehrenberg has obtained it 

 from what he considered to be the chalk marls of 

 Greece, and also in a recent state in the Baltic, 

 the North Sea, and from the coast of Cuba ; 

 Dr. Bailey has detected it at Rockaway, Long 

 Island ; and it is contained in a slide of curious 

 objects from one of the Phillipine Islands, for 

 which I am indebted to the same indefatigable 

 observer : — an interesting illustration of the 

 cosmopolite character of some of these organisms. 



Amphitetras (fig. 3.) is an analogous genus, of 

 which the end of one frustule is exhibited. One 

 species, the A. antediluviana, occurs on the British 



