254 THE AQUARIAN NATURALIST. 



lodging of its caudal termination to its eldest born, 

 and so on from generation to generation, a veritable 

 entailed property, we know not at present ; but the 

 inquiry is a most interesting one, and well worth the 

 attention of the experimental zoologist. This Sipun- 

 culus is not, however, content with the habitation 

 built for it by its molluscan predecessor ; it exercises 

 its own architectural ingenuity, and secures the 

 entrance of its shell by a plaster- work of sand, leaving 

 a round hole in the centre sufficiently large to permit 

 the protrusion of its proboscis, which it sends out to 

 a great length, and moves about in all directions with 

 the utmost facility. This proboscis is long and cylin- 

 drical, and slightly enlarged at its extremity, where it 

 is surrounded by a circlet of tentacula, which how- 

 ever are very seldom protruded. Behind these tenta- 

 cula are four circles of minute bristles. The pro- 

 boscis can be entirely retracted within the body when 

 not in use. 



The shells selected by this Sipunculus for its habi- 

 tation are usually specimens of the Stromhus Pes- 

 Pelicanus and Turritella terebra ; it is also occasion- 

 ally to be met with in Littorina littorea, when that 

 shell happens to be in sufficiently deep water ; and 

 Dentalium Entails is like wise sometimes adopted. The 

 Sipunculus Bernhardus is by no means rare ; but, as 

 it lives in from ten to thirty fathoms water, is only 

 procurable by patient dredging. 



