122 American Quarterly Microscopical Journal. 



On the return of the sea the oospore and the antheridia 

 burst their cell walls, liberating both oospore and spermato- 

 zoids. Immediately each oospore, Fig. 4, ^, is surrounded by 

 a swarm of spermatozoids {b) which fasten upon it and dis- 

 charge their contents into it. This fructifies the oospore, 

 which immediately clothes itself with a thickened cell-wall, 

 and, without a resting period, locates upon some suitable sub- 

 stance, germinates, and grows (Fig. 4, e and/). 



The Fucus platycarpus of the European coast, and the F. 

 furcatus of our own, are monoecious ; i. e., the oogonia and 

 antheridia are produced in the same conceptacle ; while F. 

 nodosus, F. vesciculosus, and F. serratus of our coast are dioecious ; 

 i. e., the oogonia and antheridia are produced on different 

 plants. 



The life history of many of the Phaeosporaceae, to which the 

 Fuci, Laminaria, and most of the olive-green Algae belong, is 

 but imperfectly known. Sachs writes, in 1874, that in many of 

 them zoogonidia are known, and in many the antheridia, but 

 not the oogonia. But Areschoug, in 1875, in some observations 

 upon the Dictyosiphon hippuroides (Observationes Phycologicae^ 

 Part Tertia, p. 25), which has been heretofore classed with the 

 Phaeospores quite as confidently as the Laminaria, or the 

 gigantic Macrocystis, has brought to light some things which 

 go far to throw doubt, in view of what Sachs says above, as to 

 whether this class of plants really belongs to the Oosporaceae. 

 The facts which he observed, viz., the conjugation of two 

 swarm-cells quite exactly like those of the Enteromorpha and 

 Cladophora and other conferva-like plants, would seem to put 

 it, and perhaps the whole of that class except the Fucaceae, in 

 the second group, the Zygosporaceae. Perhaps the supposed 

 antheridia and spermatozoids which Sachs mentions are but 

 the two swarm-spores of the class Zygosporeae. 

 {To be continued.'') 



'It was found quite impossible to get the whole of the present paper ready in time for this num- 

 ber. The remaining portion will be a discussion of the fourth class, or red Algae, in which much 

 recent work has been done, and in the fructification of some of which curious resemblances to 

 certain genera of Lichens have been noticed. 



