F. Borgesen: Phæophyceæ of the Danish W. Indies. 



59 



The tetrasporangia (I take it for 

 granted that they are such but I have 

 not seen their actual divisions) occur 

 upon both sides of the lobes of the flat 

 frond. They are scattered or some few 

 together, sometimes also confluent into 

 larger sori. They are nearly spherical 

 and have no indusium. Their diameter 

 reaches a length of about 100^ and 

 more. Scattered between the tetraspor- 

 angia groups of hairs are present. 



This species originally described 

 from specimens from St. Thomas seems 

 to be a common species on the Danish 

 Isles. It has been found in much ex- 

 posed as also in sheltered places and 

 in shallow water and deeper down to a 

 depth of about 10 meters. 



St. Croix: Northside, Casavagarden, 

 Longford, near Buck Island. 



Geogr. Distrib. West Indies. 



I 



m 



FQ-iTir, 



\iXi iHi hm i-iM-ira 

 lijj ij-j-t-jful' h Ml 



tea** 



j mVfcllUtH i ii/i/i 



jii-i-rTu*iii-HJn-'| 



Fig. 38. Dilophus guineensis 



(Kfltz.) J. Ag. Part of the 



thallus with tetrasporangia. 



(About 12 : 1). 



Fig. 39. Dilophus guineensis (Kiitz.) J. Ag. 



a, transverse section of thallus with tetrasporangia and hairs, b, transverse 



section of a sterile part of the thallus. (About 100: 1). 



