126 DINOPHYCEAE 



division which takes place either during the motile phase or else 

 during a resting phase. Spherical swarmers of the naked unicell 

 t}'pe are also known together with cysts and autospores. The 

 following represent the different morphological types that have 

 been evolved in the course of evolution : 



(a) Motile unicells which are either naked or else enclosed in a 

 delicate membrane, e.g. Desmokontae and the unarmoured Dino- 

 flagellates. 



(b) Motile unicells with a conspicuous cellulose envelope of 

 sculptured plates and with the flagellae furrows well marked, e.g. 

 armoured Dinoflagellates — Peredinium, Ceratium. 



{c) Parasitic marine forms which are either ecto- or endo- 

 parasites. 



[d) One palmelloid genus, Gloeodinium. 



{e) Colourless and rhizopodial forms. 



(/) Coccoid forms, e.g. Dinococcales. 



[g) Filamentous forms, e.g. Dinothrix^ Dinoclonium. 



Recent work has tended to show that there is no real evidence for 

 believing that this group is closely related to the Diatomaceae as 

 was formerly supposed. 



REFERENCES 



Botryococcus. Blackburn, K. and Temperley, B. N. (1936). Trans. Roy. 



Soc. Edinb. 58, 841. 

 Halosphaera. Dangeard, P. (1932-3). Botaniste, 24, 261. 

 Diatoms. Geitler, L. (1930). Arch. Bot. 3, 105. 

 Diatoms. Geitler, L. (1932). Arch. Protistenk. 78, i. . 

 Charales. Goebel, K. (1930). Flora, 124, 491. 

 Diatoms. Gross, F. (1938). Philos. Trans. B, 228, i. 

 Charales. Groves, J. and Bullock- Webster, G. R. (1920-4). The 



British Charophyta, i, 2. Ray Society. 

 General. Kolbe, R. W. (1927). Pflanzenforschwig, 7. 

 Botrydium. AIiller, V. (1927). Ber. dtsch. bot. Ges. 45, 151. 

 Dinophyceae. Pascher, A. (1927). Arch. Protistenk. 58, i. 

 Xanthophyceae. Poulton, E. M. (1926). New Phytol. 25, 309. 

 Xanthophyceae. Poulton, E. M. (1930). New Phytol. 29, i. 



