Abstract

Hypotheses on the life position of lunulitiform bryozoans have heretofore been based largely on fossils or on specimens dredged from the sea bottom, rather than on observations of live specimens in their natural habitat. Laboratory observations of living specimens of Discoporella umbellata (Defrance) and Cupuladria biporosa Canu and Bassler and associated fauna revealed that lunulitiform bryozoans survive in both apex-up and apex-down positions. Similar observations by Cook of D. umbellata and C. doma (d'Orbigny) indicated a preference by these species for an apex-up position.

During the summer of 1966, specimens of D. umbellata and C. biporosa were observed living in place in waters near Ship Island, east of the Mississippi River Delta. All specimens were in an apex-up position, with the zoarial edge partly buried by sand.

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