OLIVE-BROWN SEAWEEDS. 247 



gamete. That it should first come to rest recalls Cutleria 

 again, and in part Myriotrichia also. 



The Ectocarpacece supply us in fact with quite a crop 

 of aberrant forms, puzzling to the systematise but of the 

 highest interest from our point of view. In Ectocarpus 

 secundus and E. Ledelii, recently investigated afresh by 

 M. Bornet (10), there occur bodies to which we cannot hesi- 

 tate to apply the term antheridia. Considering other resem- 

 blances between Tilopteridacece and Ectocarpacece this matter 

 has a particular interest. The antherozoids completely re- 

 semble those of Fucus, Cutler ia and Tilopteris, and we must 

 inevitably regard them as possessing the same potentiality,, 

 The absence of a chromatophore and of reserve-material in 

 their protoplasmic contents points to an incapacity for further 

 development. The so-called zoospores of these species are 

 almost as much greater than these in size, as the ciliated 

 oosphere of Cutleria is greater than its antherozoids. 



Another species of Ectocarpus, viz., E. pusillus Griff, 

 (not E. pusillus Kutz, in which Goebel has observed con- 

 jugation — the latter is properly called E. globifer, as Bornet 

 has shown), starts another train of reflections. The spores 

 (at least those of the plurilocular sporangia) have no cilia, 

 and are immobile. This latter character does not necessarily 

 point to the Tilopteridacece, as has been held, since the 

 unilocular sporangia of E. pusillus contain a number of 

 spores, and the unilocular bodies of Tilopteridacece have 

 but one spore (or oosphere, as the case may be). The 

 loss of active mobility, however, recalls the cases of the 

 oospheres of the Fucacece, as well as the presumptive ones 

 of Tilopteridacecs, and of all three kinds (male, female and 

 non-sexual) in the Dictyotacece. In Tilopteris and Haplo- 

 spora the so-called oosphere is clothed with a membrane 

 before it is set free, but in Scaphospora the membrane is 

 not secreted until after it is set free. If we regard these 

 bodies as oospheres, the objection arises that they are set free, 

 in two of the genera, enveloped in a membrane, but it should 

 be remembered that the oogonia of Pelvetia {Fucacece) have 

 a persistent inner gelatinous membrane which does not 

 prevent fertilisation. 



