ZOOPHYTES. 38S 



ofi'euce, like the motile spines and bird's head pro- 

 cesses of the Polyzoa^ or the pedicellarioe of the 

 Echinodermata ', but it is difficult to assign a reason 

 for their peculiar situation. Thej'^ vary much in num- 

 ber and size in different specimens of Hyrlractinia, but 

 are rarely altogether absent." * 



The reflections of the able zoologist who first 

 called attention to these varied developments, and hie 

 comparisons of them with those of another polype-form 

 ■which we have lately been observing, are so interesting 

 and instructive that you M'ill not deem it needful that I 

 should apologize for citing them. " In our considera- 

 tion of the Hydraciinia^'^ he observes, " our attention 

 is arrested by the multitude of objectr, grouped together 

 to constitute a single animal, their variety in form, and 

 the sympathy which subsists between the different 

 parts. The singular spinous skeleton ; the expanded 

 membrane of the polypary, with its beautiful internal 

 network of tubes and delicate peripheric prolongations ; 

 the alimentary polyps, some white and filiform, others 

 thick, fleshy, crimson, or yellow sacs, obligingly 

 everted, to expose their interior to our microscopic 

 eye ; the reproductive polyps, with their riclil}^- 

 coloured generative sacs ; the sessile generative organs 

 of the polypary ; the ophidian, polyps, coiled in neat 

 spirals when at rest, but starting into furious action, 

 like a row of well-drilled soldiers, when injury is in- 

 flicted on the body to which they are attached ; and, 

 lastly, the tentacle polyps, floating in the water like 

 long and slender threads of gossamer, or dragging 

 up heavy loads of food for the common good ; — these, 

 together v/ith the intimate relation and sympathy sub 



* Dr. Wi ight, op. cit. 



