308 DESCBiPTioN OF [Po1ij(jastrica. 



The accompanying tabular view displays tlic further division into 

 orders and families, by Kiitzing, of the Diatomea. 



* Transverse strife unbroken. 

 Family 1. Eunotieoe 



2. MeridiesB 



3. Fragilarieaj 



* * Striae broken (interrupted) in the median line. 

 Family 4. Melosireae 



e L 5. Surirellese 



a. MONOSTOMATIC-E j 



Family 6. Cocconeideae 

 — — 7. AchnantheEB 



6. DiSTOMATICiB 



Order I, 



AstomaticaB 



Without a central < 

 opening: on the 

 secondary side. 



Order II. 

 Stomatic£B 



Ilavins; a median aperture on only 

 one of the two secondary surfaces. 



ri i 



With the central 

 opening 



Order I. 



Astoniaticae 



Without median 

 aperture on se- 

 condary side. 



Order II. 



Stomatiene 



With a large dis- 

 tinct one. 



Order I. 



Disciformes 



Order 



A])pcn(liculat;T?, -^ 

 Appended and j 

 doubtful forms. 



^ With a median aperture on each 

 \ secondary surface. 



Family 8. Cymbellere 



9. Gomphoueraea; 



■ ■ 10. NaviculeuB 



1 1 . Liemophorea) 



■ 12. Striatellece 



13. TabcUaricaj 



{- 



— 14. Coscinodisccoe 



15. Angnliferas 



16. Tripodiscea) 



17. Biddulphicaj 



18. Angulatae 



19. ActiniscecB 



In a recent volume, entitled " Species Algarum," Kiitzing docs not 

 give any tabular view of the Diatomea. 



The arrangement of the numerous genera which compose this 

 section of the family Bacilluria, presents many difficulties. Althougli 

 much has been done of late, yet much remains to be done before a 



