VOL VOX AND ITS ALLIES. 



245 



bury themselves in the hyaline envelope, and finally pene- 

 trate and become fused into the oosphere (b, Fig. 164). A 

 thick wall now forms upon the fertilized oosphere, and it 

 becomes transformed into an oospore. Thus we have in 

 these plants the transformation of an 

 individual of the colony into an oogo- 

 nium and oosphere, and the subse- 

 quent fertilization of the latter by 

 spermatozoids, which are themselves 

 fractional parts of other members of 

 the colony. 



326. The relationship of the low- 

 er Oophytes with the lower Zygo- 

 phytes, as indicated by Volvox and 

 Pandorina, is further shown by the 

 position of Sphceroplea, an undoubted 

 relative of the Confervacece (Clado- 

 phora, etc.). Spliceroplea is a free, 

 unbranched, filamentous alga, com- 

 posed of long cells joined end to end 



. & T . J , Fig. 165. Sphwroptea annu- 



(A, Fl. 165). It produces OOSphereS Una. A, ordinary filament; 



,., r.i 11 r, chlorophyll masses. .B, flla- 



111 SOme Of its filaments, each Cell ment consisting _ of oogonia, 



producing several (B, Fig. 165). 



While these are forming in one set of 



filaments, in another the protoplasm -rcr- ~~f~f"' 



becomes broken up into a multitude , fertilized oosphores, now 



. , . .,*. , ., enclosed in a thin cell-wall. C, 



Of elongated, Dl-Clliate SpermatOZOlClS tilament consisting of anthsr- 



(0 and G, Fig. 165) ; these escape 

 through lateral openings in the cells, 

 which are formed by the absorption j^ ot ; iui 



of a part Of the Wall, and then SWim- the act of being fertilized by A 



_ , spermatozoid, s. G, spi-rmato 



ming through the water they find zoids.-After osrsted. 

 their way to corresponding openings in the walls of the 



and their allies in the Oophyta, and Pandorina and its allies in the 

 Zygophyta, be placed in a common class Zoosporese. This class 

 would thus have two branches, one in the division Zygophyta, and 

 the other in the Oophyta. Such an arrangement would indicate the 

 evident relationship of the plants under consideration better than any 

 yet proposed. 



