MOLLUSCA- 



Coronu'.a Balsenaris. 



Tubiomeua Halienarum. 



The Common Bernicle, or Barnacle, at first sight, closely resemhles a mussel-shell fixed to a long stem. 

 Nearer inspection shows a difference. Its shell is composed of five pieces, and through its aperture are 

 protruded two rows of " cirrhi," or arms, which serve to entangle the small molluscs, or Crustacea, which 

 pass near them, and carry them to the mouth, where they are devoured. 



The Bernicle is always found attached to some larger object, usually floating wood, and is very common on 

 the hulls of ships. Yet, though the mature animal is permanently fixed, it has been discovered, that the 

 young are free, and capable of locomotion, nor do they finally "settle in life," until a week or two old. It 

 has previously been related how this mollusc acquired the name of " Goose-bearing." 



The Common Bernicle bears the scientific name of Pentalasmis Anatifera — the last word heing the Latin 

 for goose-bearing, which has been given to the animal on account of the ancient and exploded fable that it 

 actually produced the Bernicle Goose. 



The Tubicinella Balaenarum, or Whale Bernicle, is so called from its burying itself in the skin and fat of 

 whales, which are sometimes infested with it to an enormous extent. 



Coronula Balsenaria is wx . iicr Bernicle, also found attached to whales. 



Pollicepes Mitella ; n Bernicle found in the temperate and warm seas. 

 the principnl rap <-s, of a number of accessory pieces fixed at their base. 



Conia Poro . a Bernicle found in the Mediterranean, West Indian, and other seas, is of a sub-conical 

 form, the shell being composed of four valves. 



The lowest and simplest, in structure, of the Mollusca are the Tunicata, so named from the entire 

 dbsence of a shell, the place of which is supplied by a tunic, or outer coat, firmer than the rest of the body, 

 entirely surrounding and protecting the animal, besides being the means of its attachment to the hard sub- 

 stances whereon it commonly rests. This tunic varies in consistence, form and color, sometimes dark and 

 leather-like, sometimes cartilaginous ; sometimes exuding a gluten, which attaches sand, gravel, &c, so as 

 to form an additional envelope. Again, the whole body is soft and delicate, and the tunic is a thin, 



It is found in the South Seas. 

 It has a triangular shell, besides 



Conia Porosa. 



r379) 



Common Bernicles. 



Pollicepes Mitella. 



