rOLVOX AUD ITS ALLIES. 



245 



bury themselves in the hyaline envelope, and finally pene- 

 trate and become fused into the oosphere {h, 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 SphcBroplea, an undoubted 

 relative of the Confervacem {Olado- 

 pliora, etc.). 8ph(Broplea is a free, 

 unbranched, filamentous alga, com- 

 posed of long cells joined end to end 



{A, Fig. 165). It produces OOSpheres Um^' ^.'Trfinaly'fllammt^ 



in some of its filaments, each cell n;em°cSti,TTo„^o5if 

 producing several {B, Fig. 165). ^'i^s^&"f Jr^r^o^lni^gJ^ 

 While these are forming in one set of ™trance or spermatozoids ; 



„, , . ,11 J 1 s,s, spermatozoids entering thfc 



niaments, m another the protoplasm oogonia ; m and i, oospheres. 



1 11 ■ J. it-i 1 at the instant of fertilization : 



becomes broken up into a multitude «., fertilized oosph-res, now 

 of elongated, bi-ciliate spermatozoids aL^mlnt raLuHng oranthe?! 

 {Q and G, Fig. 165) ; these escape j^^'z^id^f^sLirXSIgK; 

 through lateral openings in the cells, S'^l'thi^ck £'atTo°f°cK 

 which are formed by the absorption '"^e. e, zoospore (vegetntive 



„ , « ^1 11 J XI • zpogonidium). F, oosphere in 



01 a part OI the wall, and then swim- the act of being fertilized by a 



. J.1 1. iu J. j-i, e J spermatozoid, «. G, spermato- 



ming through the water they find zoids— After CErsted. 

 their way to corresponding openings in the walls of the 



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

 ZygosporeiE, be placed in a common class Zygophyta. 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. 



