48. 



6. L. proboscidca Mei*. 



7. L. spicula Mer. 



8. L. semiasymmefrica Mer. 



VII. Perstriatae. — Valve usually broad, witth upper end more 

 or less acuminate, pseudoraphe very broad, striae robust (6-12 in 

 0.01 mm.). Robust forms, with thick walls. Usually sessil. 



1. L. Ehrenbergii (Kùtz.) Grun. 



2. — var. ovata (W. Sm.) Grun. 



3. — var. fungoides Mer. 



4. ~ var. subconstricta Mer. 



5. — var. tenuistriata Mer. 

 ó. L. Grunowii Mer. 



7. — var. dongata Mer. 



8. L. mediterranea Mer. 



9. — var. adriatica Mer. 



10. L. elegans Mer. 



11. i. angustata Grun. 



12. L. redondina Mer. 

 i3. Z. calif arnica Grun. 

 I4. Z. Tcamtscliatica Grun. 



Incertae sedis. 



1. L. Thtimii Mer. 



2. Z. araphidiea Mer. 



3. Z. Cro'^ierii Grun. 



4. L. longissima Leud. Fortm. 



5. Z. Baileyi Lewis. 



6. Z. niibecida (Kùtz.) Grun. 



7. Z. montercvana Mer. 



