Key to species: 

 I, Biddulphia sinensis. 2, Coscincdiscus concinnus. 3, Tluiliissiosirn i^ravida. 4. Thalassiosira nordcn- 

 skioidii. 5, Clhietoccros ciirvisclus. 6, CImetoaros decipicns. 7, Chiwtoccros dcnsiis. 8,Mclsoiirii I'oncri. 

 9, Rhizosolcniii stoltcrfotlii. 10, Rliizosolciiiii stylifonnis. 11, Rhizosolcnia alata. 12, Kitzschia dclii'atis- 

 sinia. 13, Tlhilassiothrix fraiienfeldii. 14, Thalassiothrix nitzscliioides. 15, Ceratiiini tripos. 16, Ccrtiliiini 

 loiigipes. ij, Ceratiiim fftacroceros. 18, Ceratitim ftirca. 19, Pcridinium deprcssiini. 



Photograph by James Frascr 



