102 



L. HILLIS-COLINVAUX 



Fig. 25. H. stuposa. Most of the lower half of this specimen was buried by shifting sand 

 in 1— 2-5 m of water, and holdfast filaments are present in the sand masses adhering 

 to the segments. The basal holdfast is not massive as it is in some specimens (e.g. 

 Taylor, 1950), and the thallus branching is less compact. Specimen from Enewetak 

 Atoll, Enjebi Islet, lagoon, 20 XII 75, Hillis-Colinvaux and Colinvaux. Scale bar 

 is 2 cm long. (Photograph by The Ohio State University Department of Photo- 

 graphy.) 



Geographic distribution. Western Indian Ocean, western Pacific, 

 north and south. 



This Rhipsalian Halimeda at times may resemble monile and certain 

 forms of incrassata, but can usually be identified macroscopically by its 

 short, rather thick-set appearance, the thickness of the segments 

 averaging 2 mm. Also characteristic are the relative infrequence of 

 deeply trilobed segments, and the presence of relatively short 



