184 



ZOOLOGY 



SECT. 



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

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



sgph, 



FIG. 130. Zo an thus sociatus. A, entire colony ; st. stolon. B, transverse section ; sgph. 

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

 Korschelt and Heider.) 



or tubular stolon (Fig. 130, st.). A more usual method resembles 

 that we are already familiar with 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 

 ccenosarc. Corallium and Gor- 

 gonia (Figs. 132 and 141) 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 ccenosarc. 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 Astrcva (Fig. 

 133). In the Sea-pens (Penna- 

 talacca) the proximal end of 

 the elongated colony (Fig. 

 134) is sunk in the mud, and 



FIG. 131. Hartea elegans. ftul. gullet ; 

 ,it '.<. mesentery ; sp. spicules ; t. tentacles. 

 (After Perceval Wright.) 



the distal end bears zooids 

 springing either directly from 



