TRANSACTIONS 



OF THE 



MICROSCOPICAL SOCIETY OF LONDON. 



I. — On the Structure of the Ligament connecting the Valves 

 of Conchiferous Mollusks. By E. J. Quekett, Esq., F.L.S. 



(Read March 20, 1844.) 



In examining the creatures belonging to this class of animals, it 

 will be seen that Nature, for certain wise purposes, has so ordained 

 their existence as to make them inhabitants of the water, and either 

 to be fixed or have a limited power of locomotion, and has given them 

 a protection in the shape of a shell, of dense, unyielding, organized 

 materials, their structure being unfitted for an internal skeleton. This 

 shell in great measure serves to prevent their soft bodies from be- 

 coming the prey of the voracious inhabitants of the deep, and also 

 for defending them against the violence of the waves ; to both of which 

 causes of destruction they would be continually exposed if this means 

 of defence were not given to their helpless frames. 



In one division of the molluscous animals, the creature inhabits a 

 mansion formed more or less in a spiral form. This is enlarged 

 by new growths to the orifice as the necessities of the occupant de- 

 mand, and is generally much larger than the animal within, which 

 can retract itself to some distance in its interior in the time of danger 

 from the pursuit of its enemies. It often occurs in certain species, 

 in order to render this abode more secure, that the animal has at- 

 tached to it an organ, formed generally of the same materials as the 

 shell, called an operculum, which it has the power of drawing after it, 

 and which effectually stops the mouth of the shell, and so beautifully 

 is it fitted that it would defy the best workman to adapt a piece in the 

 like manner. 



With this barrier against its enemies, the creature can live securely, 

 much more so than even we ourselves can, when we endeavour by the 



TRANS. MIC. SOC. VOL. II. B 



