IV 



PHYLUM CCELENTERATA 



195 



.f 



Sea-anemones the only simple forms are certain Madreporarian 

 corals, such as Flabellum (Fig. 156, A, B), and three genera of 

 Alcyonacea, of which 

 Hartea (Fig. 145) may be 

 taken as an example. 



The simplest mode of 

 budding- is that just de- 

 scribed in Zoanthus, in 

 which new zooids are 

 developed from a narrow 

 band-like or tubular stolon 

 (Fig. 144, st). A more usual 

 method resembles that 

 with which we are already 

 familiar in Hydrozoa, new 

 buds being formed as lateral 

 out-growths, and a tree-like 



Colony arising With nuiner- j,- IG . 144 Zoanthus sociatus. A, entire culcmy; 



rm 7-nnirU crmnmntr frm st - stolon. B, transverse section, stjph. siphono- 



OUS Z001QS Spimgmg Irom a glyphes ; d. d. dorsal, and v. d. ventral directive 



Common Stem or COenOSarC mesenteries. (After McMurrich and Korschelt and 



Corallium and Gorgonia 



(Figs. 146 and 155) are good examples of this type of growth. In 

 other cases the buds grow more or less parallel with one another, 



producing massive _ colonies 

 either of close-set zooids or of 

 zooids separated by a solid 

 coenosarc. As examples of this 

 type we may take Palythoa, the 

 most complex of the Actiniaria, 

 and many of the common 

 Madreporaria, such as Astrcea 

 (Fig. 147). In the Sea-pens 

 (Pennatulacea) the proximal end 

 of the elongated colony (Fig. 

 148) is sunk in the mud, and 

 the distal end bears zooids 

 springing either directly from 

 the coenosarc or, as in Penna- 

 tula itself, from flattened lateral 

 branches. The stem itself is 

 the equivalent of a polype. 



A very peculiar mode of bud- 

 ding occurs in the Organ-pipe 

 Coral (Tubipora). The base of 

 the original polype (Fig. 140) 

 grows out into a flattened ex- 

 pansion from which new polypes 



o 2 



FIG. 145. Hartea elegans. gul. gullet;; 

 mes. mesentery ; sp. spicules ; t. tentacles. 

 (After Perceval Wright.) 



