48 



together and sometimes also fixed together by means of rhizoids 

 or tenacula. The ramification of the filaments is very irregular, 

 branches growing out on all sides, sometimes, especially at the 

 apex of the filaments, several branches grow out secundly. The 

 cells have a very different length and short and long cells 

 are mixed together, quite as some of the cells bear branches, 

 others none. The branches grow out from the upper end of the 

 mother-cell and only one from each cell. 



The diameter of the filaments varies round about 200/^, 

 from 150—280/^. 



In one of the collections I have succeeded in finding zoo- 

 sporangia (Fig. 33). They agree very well with those I have 



found in Boodlea (comp. 

 p. 50). In the wall of 

 the cells, which are 

 transformed to zoospor- 

 angia, a single or a few 

 conical outgrowths are 

 formed. In the apices 

 of these outgrowths a 

 hole is formed through 

 which the zoospores can 

 escape. The whole cell ■ 

 contents with nuclei 

 etc. are transformed to 

 numerous small balls 

 richly provided with 

 starch, being very sim- 

 ilar to the ripe zoo- 

 spores of Valonia macrophysa as figured by Kuckuck in Bot. 

 Zeit., 1907, pi. IV, fig. 5.; more advanced stages of the develop- 

 ment I have not been able to find. 



It is often the upper end of the filaments or short side-bran- 

 ches which are transformed to sporangia, but such are also found 

 in the middle of the filaments with vegetative cells still at both 

 sides. 



As mentioned above. Clad, membranacea is a very common 

 species at the shores of the islands, occurring in shallow water 

 both in sheltered and in more exposed places. Once I have 

 taken it in a depth of about 10 meters off Frederikssted, St. 

 Croix. 



Geogr. Distrib. Florida, West Indies. 



Fig. 33. Cladophoropsis memhranacea (Ag.) Borgs. 



Zoosporangia, a, in summit; h, in the middle 



of a filament. 



