MOLLUSCA. 



The Mollusca comprise a variety of forms so great, that it is, perhaps, impossible to frame a definition 

 which shall include them all. On the one side, <he class approaches the fish so nearly, as to be hardly 

 distinguishable therefrom ; and on the other, it in like manner, approximates to the Polyfera. 



In all the Mollusca, the body is of soft consistence, and is inclosed in a soft, elastic skin, lined with 

 muscular fibres, which is called the mantle. They generally possess a complex digestive and circulating 

 apparatus, but very imperfect organs of sensa'ion and voluntary motion. The great bulk of their bodies 

 is made up of the stomach, and intestines; of the liver and other glands connected with digestion and 

 assimilation ; of the breathing apparatus ; and of the ovary for producing germs ; while the muscular 

 system is often reduced to a few scattered fibres, and rarely attains any complexity or power. 



Multitudes of the Mollusca are completely stationary, and depend for food on what is brought to them 

 by waves and currents. A few have locomotive powers, and search for their food. Most of the class have 

 shells, which are formed by a secretion from the surface of the mantle. Many, however, are without 

 shells. Therefore the ancient classification, which divided these creatures into univalves, bivalves, and 

 multivalves, according as the shells consisted of one, two or more pieces, is imperfect, and therefore they 

 are now classed by the particulars of their configuration. 



On this principle, the Mollusca may be divided, first, into those having a head, that is, a prominent part, 

 on which the mouth is located, with organs of sense near it, and those, which are acephalous, or headless. 

 These general classes are again distributed into many sub-classes. To describe minutely all these sub- 

 classes, with the special characteristics, would too greatly swell our pages. We shall, therefore, furnish 

 several specimens, briefly noting their distinctive marks, and simply state to what division they belong. 



The Cuttle Fish has a compressed, oval body, of a jelly-like substance, usually covered with a coarse 

 skin, appearing like leather. It has eight arms, furnished with numerous cups or suckers, with which they 

 seize they prey, or attach themselves to rocks so firmly, that it is easier to tear off their limbs, than 



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