NOTAMIA. 99 



cliaracter of the zooecium is totally distinct in the two : 

 while the point in which they agree — the disposition of 

 the cells, opposite to one another in pairs, is of very 

 secondary importance. 



The Australian genus Calwellia, Wyville Thomson, re- 

 sembles Notamia to some extent in the structure of the 

 zoarium, and should perhaps be included in the present 

 family. 



Genus NOTAMIA, Fleming. 



Notamia (sp.), Flem. Br. An. 1828 : Busk. 



Epistomia, Flem. Br. An. 



Sertularia (sp.), Linn£eus. 



Cellularia (sp.), Pallas. 



Cellaria (sp.), Ellis & Solander: Lamk. 



Dvnamena (sp.), Lamoiiroux. 



Gemicellaria, Blainville, 1830. 



Generic Character. — Zoarium consisting of a creep- 

 ing tubular stem and erect shoots. Zocecia united laterally 

 in pairs ; above each pair two stemmed avicularia, origina- 

 ting, one on each side, from the inferior tubular prolonga- 

 tion of one of the cells immediately above. Ocecia none. 



It is no easy matter either to determine or to explain 

 the complex structure of the zoarium in this genus. With- 

 out entering into details, it may be sufficient to state that 

 the pairs of cells do not arise immediately one from the 

 other, but that each pair is connected with the next pair 

 but one above it by tubular prolongations, which are given 

 off from the upper and inner angles of the cells composing 

 it. At each bifurcation of the shoot, the two series of cells 

 composing the internode immediately below it separate, 

 and each of them forms half of one of the branches result- 

 ing from the division ; and at this point two new series are 

 introduced to make each branch complete. The several 



H 2 



