SERTULARIAD^. 



21 



28 



29 



Family II. Sertulariad^e. 



Halecium (Oken). Corallum plant-like; stem 

 consisting of several tubes aggregated together ; 

 cells shallow cups, set on two opposite sides, 

 alternately, one under every joint. 



H. halecinum. Fig. 30 ; n. s. and mag. 

 Beanii. 

 muricatum. 



Sertularia (Linn.). Corallum plant-like; stem 

 simply tubular, branched, jointed ; cells vase-like, 

 with everted brims, alternate or in pairs, set on 

 opposite sides. 



