HYDRACTINIA SQUAMATA. 117 



which it often brings into shallow water, or almost to 

 the shore. Such shells, conveyed by the new tenant 

 from greater depths, are often profusely invested with 

 the animal in question ; therefore, the capture of a 

 number of Hermit Crabs, thus sheltered, will give the 

 observer a fair chance of finding specimens of these 

 creatures. 



The Hydractinia squamata dwells in numerous 

 colonies, which are always implanted on empty shells, 

 such as those of the Nerita, Murex, Tritonium, &c. 



The animals themselves are single, though nume- 

 rously associated : a portion of the largest whorl of 

 a decaying shell is sometimes invested by many hun- 

 dreds of them, resembling a snow-white fleece. 



The colony seems to be originally founded on the 

 epidermis of the shell, to which the animal is attached 

 by a slender stalk, enlarging above, so as to present 

 somewhat of a club-shape, whence it has commonly 

 obtained the somewhat inappropriate name of Coryne 

 (/copuvrj, a club). This enlargement or head is envi- 

 roned by from four to about twenty-five tentacula, 

 arranged in successive stages. They are all, together 

 with the summit, very extensile and flexible, and en- 

 dowed with an adhesive property. Their resemblance 

 to the human fingers is such, that Sir John Daly ell was 

 led to confer upon this zoophyte the name of Hydra 

 digitata. 



The stomach of the polyp is confined to the dilated 

 portion or head, which is more opake and solid than 

 the medulla in the stalk, and distinctly separated 

 from it behind. Apparently the horny sheath or skin 

 entirely encloses it, but at intervals the paler apex 



