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 



FUj. 143 — Zoantbus SOCiatus. A, entire colony ; st. stolon. B, transverse section, '^i/ph. 

 siphonoglyphes ; d. d. dorsal, and r. <f. ventral directive mesenteries. (After McMun-ich and 

 Korscheit and Heider.) 



or tubular stolon (Fig. 143, s<). 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 Palythua, the most com- 

 plex of the Actiniaria, and 

 many of the common Madre- 

 poraria, such as Astrari (Fig. 

 146). In the Sea-pens (Penim- 

 tuhirea) the proximal end of 

 tlie elongated colonj' (Fig. 

 147) is sunk in the mud, and 

 Fig. i44.-Hartea eiegans. ,r/„7. gniiet ; the distal end bears zooids 

 DIM. mesentery ;.'.7.. spicules ; (.tentacles. springins' either directlv from 



(After Perceval Wnght.) loo •J 



