EXPLANATION OF PLATE XXVIII. 



ig. 1. Glcnodinium nibrum, sp. n., dorsal aspect x 1000. 



2. Ditto ventral aspect. 



3. Ditto example without the cuirass. 



4. Ditto empty cuirass. 



5. 0, 7. Ditto examples showing the formation of the 



resting spores. 



8. Gymnodinium spiralc, Bergh., after Bergh. 



9 - 15. Dino^yhysis homunculus, Stein., showing progressive phases 

 of development ; highly magnified. 



16. Ditto example dividing by longitudinal 



fission. 



