18 Acta Societatis pro Fauna et Flora fennica, VIII, n. 2. 



natural genus. Nearly related to some forms of Aehnanthes are 

 Cocconeis and Orthoneis and to the latter Mastogloia. 



The natural system of the diatoms with a median line (Ra- 

 phidese) seems, then, to be represented by the following arrangement. 



fXit^rhin, PlnmntmniJ Amphoropsis — Amphora p. p. 



(Mitzsclna) — Flagiouopis^ Amphiprora _ pi eu rosigma - Navicula (Vegas CI.) 



Nav. radiosae. 

 (see below). 



Pinnularia — ? — X. limosae (?) 



Schizonema (ramosissimum-group.) 



\r it™™) Punctatfe (see below). 



Nav. radiosce{ mioicone ^ iR Bolleana) . 



Trachyneis (Nav. velata, N. pulcliella. Alloioneis Kurzii, Al. 

 antillarum). 



I? Group of N. triundulata — ? Diploneis — ? — Amphora p. p. 

 r 1 oil / Gomphonema. 

 ^ L}mUeUa \ Amphora p. p. 

 Lyras. 

 Decipientes (see below). 



Xav. decipientes 



Rhoiconeis (R. Garkeana). 

 Scoliopleura (S. tumida). 



[ ? Amphiprora. 

 ComplexjeJ Schizonema (comoides-group). 



{ Amphora p. p. 



Nav. formosce 



Quadriseriatre p. p. 

 r . (? Pinnularia. 



? Palpebrals. 



? Nav. Schneideri — Scoliopleura p. p. 



? Amphora p. p. (A. Grevilleana). 



C Amphipleura, Berkeleya. 

 Frustulial Brebissonia. 



( ? Anomceoneis. 



[ Orthoneis, Mastogloia. 



n . I Aehnanthes. 



Cocconeis Campyloneis . 



I Rhoicosphenia. 



I have in the above exposed my views about the arrange- 

 ment of the naviculoid diatoms, but I must confess that I am not 

 at the moment prepared to propose it as a definite system. There 



