162 



It grows in the littoral and uppermost part of the sublittoral 

 region, most often in sheltered places, but also in more exposed 

 and seems to be a common species. 



It was found, St. Croix: Ghristiansteds Harbour and in the lagoon 

 near this town. St. Thomas: The Harbour in several places. St. Jan: 

 Cruz Bay and off America Hill in a depth of about 20 metres. 



Geogr. Distrib. West Indies. 



Fig. 129. Ectocarpus Mitchellse Harv. 



a, part of thallus with plurilocular sporangia, b, part of thallus with young 



branchlets. c, chromatophores in a young cell, d, chromatophores in an 



older cell, (a and b, about 100: 1; c and d, about 200: 1). 



2. Ectocarpus Mitchellae Harv. 

 Harvey, Nereis Boreali-Americana, Part I, p. 142, pi. XII, G. 



The specimens referred to this species form two — three cm and 

 higher tufts. 



From the lowermost cells in the filaments rhizoids grow 

 out (Fig. 130), fixing the filaments to the substratum, stones, shells 



