EXPLANATION OF PLATE XI. (con ti nued). 



FIG. 



22. ARCYRIA CINEREA, Fries. A single sporangium, completely filled with half- 



matured spores, x 25. 



23. PHLEBOMORPHA RUFA, de Bary. Portion of horny rete or capillitium, with 



enclosed spores, x 390. 



24. DIDYMIUM SERPULA, Fries. Section of sporangium, showing contained 



spores. 



25-28. LYCOGALA EPIDENDRON, Fries. 25, Two isolated spores ; the one at a bursting 

 and liberating its monadiform germ, x 390 ; 26, three fully developed, free- 

 swimming, highly polymorphic monadiform zooids, developed from the 

 spores represented in the preceding figure, x 390; 27, amoaboid condition 

 assumed by the same monadiform zooids, representing the first step towards 

 the development of the compound plasmodium ; 28, Young repent amcebi- 

 form plasmodium formed by the coalescence of several of the smaller 

 amoeboid particles. 

 29. yETHALiUM SEPTICUM, Fries. Young repent plasmodium, x 200. 



30, 31. DIDYMIUM FARINACEUM, Fries. 30, Fragment of peridium or indurated outer 

 wall of sporangium, containing substellate calcareous spicula, x 390 ; 31, an 

 isolated spicule from the same peridium further enlarged. 



32-35. DIDYMIUM SERPULA, Fries. 32, 34, Polymorphic monadiform zooids, the 

 example at 32 with ingested food-particles ; , nucleus or endoplast ; c v, con- 

 tractile vesicle, x 350 ; 35, amcebiform condition of a similar monadiform 

 zooid, x 350. 



36-38. TRICHIA VARIA, Pers. 36, Isolated spore, x 390 ; 37 and 38, the same spore 

 with its wall ruptured, and giving exit to a free-swimming monadiform 

 zooid. 



39. DIDYMIUM LIBERTIANUM, Fres. Minute subaqueously developed sporangium, 

 with nine or ten contained spores, x 390. 



40-44. STEMONITIS OBTUSATA, Fries. Successive phases of multiplication by fission 

 of a monadiform zooid, X 390. 



45-47. DIDYMIUM LEUCOPUS, Fres. Young repent amcebiform plasmodia, containing 

 (c v, -v c] numerous contractile vesicles, the plasmodia at 45 and 46 being 

 in a contracted, and at 47 in a fully extended state, x 350. 



