14 EEPOET OF COMMISSIONER OF FISH AND FISHERIES. 



Bryopside^e. — In the present paper this suborder includes a single 

 species of our coast, Bryopsis plumMa, which consist of a single cell of 

 very large size, which branches in a pinnate fashion. When about to 

 reproduce, some of the branches are shut off from the rest of the frond 

 by a cell-wall, and the contents are then transformed into zoospores. A 

 conjugation has not yet been seen in this species. From its unicellular 

 structure one might suppose that Bryopsis should be placed near Vauch- 

 cria, but. no oospores have yet been observed like those in the last- 

 named genus. In the absence of a knowledge of the development of 

 the genus, it is retained as a divsion of the Zoosporece, differing from the 

 Chlorosporece in the unicellular character of the frond. 



Botrydie^e. — The development of Botrydium granulatum, which was 

 fully studied by Rostafinski and Woronin, differs from that of the 

 Chlorosporece which we have already described in the fact that there is 

 first produced in the small unicellular frond of which this species is 

 composed a number of round spores, or more properly zoosporangia, 

 which are discharged from the mother cell. There is then formed in 

 each zoosporangium a number of zoospores, which escape and conjugate 

 with one another. De Bary and Strasburger have described a similar 

 process in Acetabularia mediterranean and have applied the name gameten 

 to the zoospores which conjugate, and zygote to the body formed by con- 

 jugation. Secondary modes of reproduction by means of zoospores with 

 a single cilium and so-called root-cells occur in Botrydium granulatum. 

 Botrydium (Codiolum) gregarium, our only marine species, resembles B. 

 granulatum, but its development has never been fully studied. 



Ph^eospore^e. — The Phevosporew are all marine, with one possible ex- 

 ception, and are, when growing, of an olive-brown color. They possess 

 only one form of zoospore, which is more or less oval and pointed at one 

 end and olive-brown in color, and are furnished with two cilia attached at 

 one side and a red spot. The zoospores are not born indefinitely in any 

 cell, but are produced only in certain cells or sporangia. Each species is 

 supposed to have two kinds of sporangia : one called the unilocular spo- 

 rangium, which contains a large number of zoospores, and another, called 

 the plurilocular sporangium, which consist of an aggregation of small cells, 

 each of which contains a single zoospore. The name of oosporangia 

 was originally given by Thuret to the unilocular sporangia because they 

 are usually more or less oval in shape, but he afterwards abandoned the 

 name because it is more appropriately applied to the spores of the 

 Oospores. The older name of trichosporangia, which was at first applied 

 to the plurilocular sporangia, has also been abandoned. Although, as 

 has been said, each species is supposed to have both kinds of sporangia, 

 in a large number of species only one kind has as yet been observed. 

 Both may occur on the same individual and at the same time, but more 

 frequently they are found at different seasons of the year. Although 

 found all over the world, the Phceosporece particularly affect the temperate 

 and arctic regions, and they fruit more abundantly, as a rule, in winter 



