" especes sont en general lisses, brillantes, et il ne parait pas qu'aucune d'elles soit pourvue de 

 " drap marin."* 



A careful collection of the shells of these Testacea has enabled the author to state from 

 actual experience that the majority of species recorded by Lamarck are provided with the " drap 

 " marin;" and he is induced to believe that few, if any, of the species of Cymba, Melo, or 

 Voluta, are entirely without it. The species of Cymba have not only this drap marin, but also 

 the additional protection of a glaze, or vitreous pellicle, more or less extended over the shell. 

 This last is increased as the animal advances in age; and, in some species, as in Cymbse probosci- 

 dalis, porcina, rubiginosa, &c. forms a complete surtout, which, in old specimens, has such an 

 appearance as has led more than one uninitiated spectator to inquire whether a thick coating of 

 enamel had not been poured over the shell. 



But the want of the soft parts is forcibly felt by the conchologist who aims at a higher 

 object than giving a name to a new species. Till we have an oppoi*tunity of observing these 

 animals, till we have them under the dissecting-knife, their proper place in the scheme of 

 nature can never be satisfactorily known, and our best attempts at placing them according to 

 their exuvia? will be the result of little more than conjecture; but an intimate acquaintance 

 with their anatomy, as adapted to the construction of the shell, and a knowledge of their 

 habits of life, would dispel much of the obscurity which still hangs over the animal economy 

 of the testaceous Mollusca, and would afford materials for general conclusions. 



Much, indeed, has been said by Comparative Anatomists, but a great deal remains undone ; 

 and however reluctant our vanity may be, to leave the subject on which we are employed open 

 to the correction and improvement of those who will come to the elucidation of it with increased 

 knowledge, we must be content to add the little light which our information enables us to give, 

 and cheerfully to labour according to our strength in clearing the path for those who are to 

 come after us. These Monographs are produced with any feeling but that of infallibility, and 

 the errors of the Author will serve as landmarks to warn those who may hereafter embark in 

 the same inquiry. 



* Anim. sans vertebres, Tom. VII, p. 323. 



