IV 



PHYLUM CCELENTERATA 



197 



The simplest mode of budding is that just described in Zoan- 

 thus, in which new zooids are developed from a narrow band-like 



B 



sgplv 



FIG. 143. Zoanthus sociatns. A, entire colonj* ; st. stolon. B, transverse section, sgph. 

 siphonoglyphes ; d. <l. dorsal, and r. </. ventral directive mesenteries. (After McMurrich and 

 Korschelt and Heider.) 



or tubular stolon (Fig. 143, st). A more usual method resembles that 

 with which we are already familiar in Hydrozoa, new buds being 



formed as lateral outgrowths, 

 and a tree -like colony arising 

 with numerous zooids spring- 

 ing from a common stem or 

 coenosarc. Corallium and Gor- 

 gonia (Figs. 145 and 154) are 

 good examples of this type of 

 growth. In other cases the 

 buds grow more or less paral- 

 lel with one another, producing 

 massive colonies either of close- 

 set zooids or of zooids separ- 

 ated by a solid coenosarc. As 

 examples of this type we may 

 take Palythoa, the most com- 

 plex of the Actiniaria, and 

 many of the common Madre- 

 poraria, such as Astrcea (Fig. 

 146). In the Sea-pens (Penna- 

 tulacea) the proximal end of 

 the elongated colony (Fig. 

 147) is sunk in the mud, and 



Flo . i44.-Hartea eiegans. gvi. gullet -, the distal end bears zooids 

 &Sv^v$$!^' " tentacles - springing either directly from 



