APPENDIX. 



321 



the polypitcs of this family should have eluded the obser- 

 vation of so many excellent naturalists. Prof. Filippi tells 

 us that in his aquaria, towards the middle of April, the 

 free zooids of Clavatella prolifera were present " in numero 

 incalcolahile ; " yet he seems never to have traced them to 

 their stock. 



The polypite is minute and exceedingly slender; but 

 when extended, its milk-white colour makes it easy to 

 detect in a good light. It is very limited in its habitat ; 



Pig. 18. 



Gronozooid of Clavafelln. with young budding. 



and the small clean pools, on the higher rocks between 

 tide-marks, in which it delights are readily examined. It 

 is not a denizen of such as are thickly overgrown with 

 weed. Coralline, and a delicate bright-green alga which 

 grows in small tufts, constitute the chief vegetation of the 

 haunts of the Clavatella. 



It loves the freshest and purest water, and, frail as it 

 seems and is, it is found amidst the tumultuous dash of the 

 waves on the most exposed portions of the coast. When 

 contracted, the body shrinks down amongst the algae, or 



v 



