Fig. I20. — Ooganious sexual reproduction among the Algae. A-D, 

 Qidogonium. A, Part of tliread of 0. pachyandrium showing antheridia 

 (a.) with spermatozoids (sp.) ; B, oogonium of 0. concatenatutn, with 

 two dwarf-males (d.m.) ; C, oogonium of 0. diplandrum showing the 

 spermatozoid penetrating into the egg at the receptive spot (r.s.) ; 

 D, antheridia of 0. landsboroughi, with escaping spermatozoids. 

 E-G, Vaucheria sessilis. E, Oogonium (?) and antheridium ((J) ; 

 F, oogonium with oospore and dehisced antheridium ; G, spermato- 

 zoids. H-L, Funis. H, Oogonium with surrounding hairs ; I, 

 branched hair bearing numerous antheridia (a.) ; J, young plant ; 

 K, liberation of spermatozoids ; L, spermatozoid. (A, B, and E> after 

 Hirn ; C after Juranyi ; E-G after Sachs ; H-K after Thuret ; L after 

 Guignard.) 



