220 



longer, in the young cells rather broad (Fig. 206 B), in the older 

 cells narrower, irregularly sinuate ribbons (Fig. 206 F). Each cell 



Fig. 206. Callithamnion byssoides Am. 



A, B, branches with tetraspores (75:1), (150:1). C, carpogonial branch 



with trichogyne (160:1). D, young cystocarp (160: 1). E, older cystocarp 



(75:1). F, cell with chromatophore (75:1). 



contains a single nucleus (Fig. 206 B), but I wish to point out that I 

 have not succeeded in seeing the nucleus in the older and larger cells. 



The plant was found with cystocarps, anthe- 

 ridia and tetrasporangia in the months of January 

 and February. It occurred in shallow water, in a 

 sheltered place upon the roots of the mangroves 

 or upon other alga3 growing here. 



St. Croix: The Lagoon of Christiansted. 



Geogr. Distrib.: Atlantic coast of Europe and 

 North Africa, Mediterranean Sea, Atlantic coast of North 

 America, West Indies etc. 



3. Callithamnion spec. 



This plant being quite sterile (only once a speci- 

 men was found with a few nearly ripe tetraspor- 

 Fig 207. angia) I have not been able to determine it exactly, 



Callithamnion ' => ' 



byssoides Am. but as it was found abundantly in some places 

 Antheridial m ^ ee p wa t er j j us t want to give a short des- 



{About 350 : l). cription of it and a few figures too (Fig. 208). 



