Fig. 487. 



MORPHOLOGY OF EEPBODUCTIVE ORGANS 225 



of the gametes of isogamous plants (fig. 488). The shape is 



usually olavate or filamentous, and with very few exceptions 



these gametes have no cell-wall. 



They are known as antherozoids. 



In most Red Seaweeds they have 



no cilia, and become clothed with 



a ceU-waU after their liberation 



from the gametophyte. In certain 



of the Fungi, especially the 



Lichens, similar bodies occur, 



which always have a cell-wall. 



Both these are frequently called 



spermatia, to distinguish them 



from the motile forms. There is 



some doubt as to the true nature 



of the spermatia in the latter 



group, many botanists inclining 



to the view that they are gonidia, 



and not gametes. 



Throughout the groups of the 

 Mosses and Vascular Cryptogams 

 the ciliated antherozoid is always 

 found {fig. 488). 



In other forms, in which the 

 coalescence does not take place by 

 means of water, the differentiation 

 of the male gamete is much less 

 marked. It is only a mass of un- 

 differentiated protoplasm, usually 

 of very smallsize. It never escapes 



^yy- 



Fig. 487. Conjugation in Mucor Mu~ 

 cedo. h. Two hypliEe which have 

 come into contact at their apices, 

 and each has cut off from itself a 

 cell. zyg. Zygospore resulting from 

 the fusion of these cells, zyg,^ 

 Adult zygospore after germination . 

 p. Promycelium bearing a sporan- 

 gium, 5^. 



Fig. 4«8. 



Fig. 488. a. Antherozoids of Moss ( x 1200). a. Antherozoids of Fern ( x 700). 



from the seat of its formation until conditions are such as to 

 enable it at once to coalesce with the female gamete. This form 

 is found in many Fungi, such as Cystopus, and in the flowering 



VOL. I. Q 



