BRTOZOA 



255 



opening of ooecium round or oval: a northern species; on rocks, shells, 

 etc., from shallow to deep water. 



FAMILY 6. FLUSTRIDAE. 



Colony horn-like and flexible, erect, expanded, and foliaceous, usually 

 consisting of broad branches attached by a narrow base; zooecia contigu- 

 ous and multiserial : 6 genera. 



FLTTSTRA L. Colony frond-like ; zooecia in 1 or 2 layers, more or less 

 quadrangular in form, rounded above, with a raised margin; avicularia 



Fig. 415 



Fig. 416 



Fig. 417 



Fig. 415 Cellaria flstulosa (Cambridge Natural History). Fig. 416 Flustra foliacea 



(Cambridge Natural History). A, entire colony ; B, several zooids. 



Fig. 417 Membranipora pilosa (Osburn). 



resembling the zooecium and usually in line with them; ooecia concealed: 

 several species. 



F. foliacea (L.) (Fig. 416). Colony brownish in color, with a dis- 

 tinct odor of violets when fresh, up to 15 cm. high; zooecia in rows and 

 in 2 layers with 2 spines on a side; ooecia very shallow, the opening 

 forming an arch over the upper end of the zooecium: a northern species 

 occurring on stones, shells, etc., in shallow water. 



FAMILY 7. MEMBKANIPOEIDAE. 



Colony calcareous or partly membranous and flattened, being in- 

 crusted on stones, shells, or seaweed, occasionally erect; zooecia often more 

 or less rectangular and with raised margins : several genera, with 150 species. 



MEMBRANIPORA Blainville. Zooecia with raised margins and a 

 depressed front wall which is wholly or partly membranous, and placed 

 beside one another horizontally, forming a more or less irregular crust : 12 

 species near Woods Hole. 



M. pilosa (L.) (Fig. 417). Zooecia ovate, narrowed below, thickly 

 punctured with minute oval pores and often with a silvery sheen; margin 

 thickened, with 4 to 12 spines and just below it a corneous spine, some- 

 times short anc] sometimes very long; no ooecia; on stones, etc., frpm tide 



