wliicli though inferior in organic development to the inner or enclo-skeleton 

 of the higher orders, nevertheless exhibits certain characters and impressions 

 indicative of peculiar structui-es, and affording good subsidiary characters 

 for the distinction of groups. 



The Conchologist must look upon his shells, in the absence of the living 

 parts, as a portion of those imperishable ^'Medals of Creation'"^ whose his- 

 tory is suggested by their structure and animal impressions. The CotvreT/ shell 

 may be knowTi by its highly polished porcellanous surface, to be more or less 

 entirely enveloped by some appendage of the animal ; the Siphonaria shell 

 offers indications of a siphon ; the Veims shell shows the form of the lobes 

 of the mantle ; and who that regards the Haliotis shell with a discerning 

 eye, can fail to surmise that there must be some special design in its series of 

 holes, wliich he may learn have been perforated by the animal in its pro- 

 gress of growth for the passage of the breatliing organs. To show, too, 

 that the most opposite forms may yet exhibit indications of zoological affinity, 

 it may be observed that the Siliqtiaria shell possesses a structure similarly 

 adapted, and of the same nature, as that first spoken of in the Haliotis. Here 

 is an unlocked for affinity ! An intimate zoological relation between shells 

 exhibiting the two extremes of convoluted forms ; — the depressed spire, and 

 the tubular spire. 



Comparative Rank in the Animal System. 



A brief survey should now be taken of the Animal Kingdom in order to 

 show the rank and comparative importance of the Mollusca in the general 

 range. We are encompassed by a mass of living beings, of whom we our- 

 selves constitute the grand type, whose nature and properties present a 

 strange complication of affinities. Tor the sake of studying the several 

 atoms of this complicated mass, and arranging them in order for reference, 

 each individual is described and named according to what is called a bino- 

 mial method ; that is, a method of two names, one denoting its general or 

 generic character, the other its particular or specific character. And that 

 the nomenclature may be of universal application, and acknowledged by all 

 tongues and countries, it is adopted in the Latin. 



The modifications of nature are of that nice and delicate character, that 

 we may trace a certain gradation of affinity from man to the animalcule. 

 Although objects of extremely anomalous nature occur to disturb the subtile 

 reasonings of the philosopher, yet, there is a wonderful link of relationsliip 

 between the highest animal, man, in whom the beauty of organization is 

 complete, and the lowest creatui'e, the animalcule, in which organization is 

 so simple as to present nothing more than a globule multiplying with com- 



Mantell. 



DS\ 



