SABELLA. 177 



the body ; another is considerably prolonged, so as to afford a safe re- 

 treat in times of danger. The architect of a third seems to persist in 

 advancing the fabric as long as it can procure materials. It never 

 wearies of working, thus sharing the nature of the Terebella, of which 

 more hereafter. 



Night is the chief season of architectural labour, though perfect 

 idleness never leaves the day unoccupied. 



By means of the tentacular organs, and the cleft in the anterior 

 part, grains of sand are selected and adapted to the precise spot, where 

 glutinous matter secures them to the tube for sheltering its otherwise 

 defenceless tenant. 



Among the most interesting instincts displayed in animal life, are 

 those whereby weak and unresisting creatures shew their gift from 

 Nature in rearing the means of self-protection. 



I know not that an individual animal, if adult, is capable of found- 

 ing a tube, but rapid advances extend that which is already in progress, 

 and in repairing the breaches of those which are injured. 



This may be readily witnessed by the inquisitive observer. 



On one occasion the dwellings of a colony of Sabella had been acci- 

 dentally impaired, so as to leave them only about half an inch in height ; 

 but on a supply of sand, it became soon evident that a member of the 

 community, more active than the rest, had constructed a tube not less 

 than two inches and a half in length. In endeavouring to ascertain their 

 preference for particular substances, I supplied this specimen, among 

 others, with brick dust and pounded glass. Only a few particles of each 

 being used in a week, shewed them to be unsuitable, therefore I removed 

 the architects to a bed of sand. The active Sabella did not now relax 

 in its industry. Sometime afterwards it was accidentally buried during 

 weeks among mud, which it survived with impunity ; and it next em- 

 ployed itself in extending its cylinder still more and more with sand and 

 shelly fragments. 



As the habits of such creatures may be rendered subservient to tin 

 curiosity of the observer, who desires a distinct view of their operations 

 while unrestrained in their own dwellings, he must watch the time when 



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