SEXrALITT IIT THE LOWER CRYPTO GAMIA. 75 



swim about freely in tlie water. They are oval, nearly filled with a 

 green substance, but having a transparent beak surrounded by cilia. 

 After some time the androspores attach themselves by the beak to 

 the oogonia, the cilia fall oif , and they then commence a true vegeta- 

 tive growth and become transformed into an organ which produces 

 spermatozoa. In some cases the cavity of the androspore gives im- 

 mediate birth to two spermatozoa; in other cases a septum is formed 

 dividing the androspore into two cells, the upper one of which pro- 

 duces two spermatozoa : in other cases again several septa are formed 

 giving rise to several cells in each of which cells two spermatozoa 

 are produced.* 



The point to which we have alluded in speaking of the Fucacese — 

 viz., whether impregnation is effected by contact merely, or whether 

 the spermatozoa are absorbed in the rudimentary spore has been much 

 discussed in the case of the (Edogonieae. ^ Pringsheim, De Bary, and 

 Petrowski being ranged on the one side, and Yaupell on the other. 



In the JahrbiJcher fiir wissenschaffcliche Botanik, Vol. ii. p. 

 1-36, Dr. Pringsheim gives the results of his observations on the 

 genus CoJeochcEte. Here again we meet with oogonia and sperma- 

 tozoa, the former being impregnated by the latter so that the 

 sexuality of these plants also may be considered to be established.f 



"With regard to the nature of the Saproleguieae much diff"erence 

 of opinion has existed and still exists, some botanists considering 

 them to belong to the Pungi, others to the Alg89. Mr. Berkeley's 

 opinion (and none could be more valuable) was, and we believe still 

 is, in favour of their being submerged conditions of mucedinous 

 Pungi, but we think the majority of botanists still rank them as 

 Algje.J However this may be, the observations of Pringsheim and 

 De Bary show that impregnation is efiected by the operation of active 

 spermatozoa upon membraneless *' primordial spores," a process pre- 

 cisely analogous to what we have already stated to take place in 

 Fucits, (Edoffonium, and SpTicBvojplea. We have not space to enter 

 into details with regard to the structure of the oogonia and anthe- 

 ridia, but it is worthy of remark that in all the three genera of the 

 family — viz., Saprolegnia, Aclilya, and Pythium^ the spermatozoa 

 reach the contents of the oogonia {i.e., the so-called 'primordial spore) 



* In (Edogonium curvum, Pr. it appears that only one spermatozoon is produced 

 in eacli antheridial cell. 



t On the peculiarity of the fructification of the Coleochaeteae and their relations 

 to the Mosses and Characeae, see the papers above cited, pp. 24-29. 



X See Jahi-b. flir wiss. Bot. Vol. i., p. 284, Vol. ii. pp. 169 and 205. 



