PENXATULID^. 61 



the fleshy part of the animal and its polypes; while in the 

 Asteroid groups, ineluded in the famihes of TennaUdidce 

 and GorgoniadcE, the skeleton consists of a central hornv 

 or calcareous axis^ around which are arranged the poljpe- 

 bearing fleshy parts. 



Pennatula phosphorea. 



Dr. Johnston thus describes, in technical terms, the 

 genus : — "Polype-mass free, plumous, the shaft subcylindric, 

 naked beneath, pennated above ; pinnse two-ranked ; spread- 

 ing, flattened, and polypiferous along the upper margin."" 



"Nature," observes Lamarck, "in forming this compound 

 animal, seems to have desired to produce a copy of the ex- 

 terior form of a bird^s feather.''^ 



And truly, if you imngine a bird^s feather four or five 

 inches long, but of a fleshy substance, plumed broadly at 

 the feather end and naked at tire quill end, very elegant in 

 form and of a delicate pink colour, you have before you an 

 image of our Pemiatula : yet this also is a living ammal. 

 Along the upper edges of the pinnae are placed the polype- 

 cells, in rows, containing the polypes. The pinna3 are 

 obliquely curved backwards, and each one is capable of an 

 independent action. All the external part of this Zoophyte 



