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than the results derived from my inquiry into their organic formation would 

 fully warrant. I have in some instances, particularly in the representations of 

 the tentaculated fingers, figured specimens as perfect, where well preserved 

 portions furnished me with data sufficiently clear and demonstrative, and thus 

 enabled me to save the reader the irksomeness and trouble of deciphering for 

 himself mutilated fragments. I have in most instances omitted the represen- 

 tation of the surrounding matrix, as unessential to a history of the organic 

 formation of the animals. 



I have followed in all these points M. CUVIER, who, in arranging the bones 

 of the Paris bason, was enabled by his great knowledge of comparative 

 anatomy, to appropriate each single bone to its proper species and place, and 

 thus to re-unite and restore perfect skeletons from the scattered members dis- 

 persed in various separate blocks. By pursuing this method, he has enabled 

 every one tolerably acquainted with the subject, to form a general and correct 

 idea of the form of these long extinct species, and to assign to them their true 

 places and stations in the systematic order of nature, purposes which must 

 obviously have been accomplished in a far less satisfactory manner, even if they 

 had not entirely failed, had he contented himself by figuring each separate 

 slab, a process by which the most essential features would have been lost, and 

 buried beneath the accumulation of unessential details. 



1 would indeed generally remark that I must always consider the repre- 

 sentations of mutilated fossil specimens imbedded in their mineral matrix, 

 prejudicial to the advancement of a real knowledge of organic remains, when- 

 ever sufficient certainty can be obtained to effect a perfect restoration of the 

 object without risking conjectural additions. This practice, at best, affords 

 only a fairer opportunity to the artist for the display of his art, while it mate- 

 rially detracts from the information which the representation is calculated to 

 afford to the physiological inquirer, who by a general figure acquires at 

 once an idea of the whole animal, and is at the same time enabled to judge 

 of its correctness, by referring to the representations of the anatomical details, 

 and to those general laws of organization which belong to the classes most 

 nearly approximating in structure to the individuals under examination. 



In pursuance of the plan adopted in modern publications on natural 

 history, by M. CUYIEK, M. SAVIGNY, &c. I have used letters and signs denoting 



