534 



COSCINODISCUS. 



and notes, as well as Eulenstein, considered it a Podosira. I am equally of 

 opinion that it not a true Coscinodisais. 



Planktoniella Schlltt, 1893. A genus created for Coscinodisais 

 So/, which is distinguished by the membranous ala surrounding the valve, 

 and by the baculiform appearance of the girdle face. This diatom, besides 

 being very rare, deserves to be raised, in my opinion, to the 'rank of a 

 genus. 



Fig. 279. Planktoniella Sol. 



Antelminellia Schiitt, 1893. A genus created for 

 Coscinodisais Gazelhz of Janisch (plate 34, fig. 902 of this work). This form, 

 which has the structure of C. concinmis, is distinguished by its large size, which 

 reaches almost to 2 mm., and by the small spines found on the central portion. 



