222 Natural-Historical CoUeclions. 



is precisely similar to many others which we employ without scruple, because 

 language does not supply us with such as are perfectly rigorous. 



Aristotle was much happier in the application of his method to the study of 

 living objects. His History of Animals, in particular, is a noble production. 

 ( To be continued.) 



On the Organic Composition of the Shell of Molluscous Animals ; by M. J. 

 B. Robineau-Desvoidy. — In the Annales des Sciences d'Observation for 

 February last, there is an elaborate memoir by M. Robineau-Desvoidy, in which 

 he endeavours to prove that the shells of molluscous animals possess an organic 

 structure, which refers them to the vertebral apparatus. " It might be imagi- 

 ned," says he, " that the discovery of the principle mentioned must have cost me 

 long and laborious researches. But no ; I had only to make use of my eyes. I 

 betook myself to the rich galleries of the Natural History Museum of Paris, and 

 after a few visits, the theory, thanks to its extreme simplicity, was completed." 

 The author then states, that having embraced no opportunity of hearing public 

 lectures on the moUusca since 1818, and living retired in the country, without 

 access to books, he does not pretend to know all that may have been may been 

 done in this department, and therefore, should he, in announcing his discoveries, 

 speak of things already known, he is not desirous of any unmerited honour. 

 " The principal results," he continues, " were communicated to the Natural 

 History Society of Paris, in December 1827; I might therefore have delivered 

 them to science before now, but I had to wait. The publication of my inquiries 

 respecting the vertebral organization placed me in the most critical position, and 

 under the influence of the treatment which this production receives, I could only 

 look upon myself as similar to one of the Parias of India, who are condemned 

 never to raise their heads in their native country. My judges did not even deign 

 to make mention of me in the account given of a pubhc meeting. My resigna- 

 tion was great, and I contented myself with crying : Ira hominum transibunt, 

 utinam scripta nostra maneant .'" 



The idea that the shell of molluscous animals might be referred to a vertebra, 

 or a solid vertebral apparatus, might seem foreign to the circle of his previous 

 studies, they having been confined to the articulated animals, in which he had 

 traced the solid organs of the vertebrated or higher animals. These articulated 

 animals presented a multitude of appendages, variously constituted. They had 

 their periphery surrounded by calcareous apparatus, which might easily be com- 

 pared to the solid bony frame, but not to the scales, of a tortoise. But the laws 

 established according to this theory for regulating the mode of classification of 

 these animals, suddenly cease when we cast our eyes upon the vast family of the 

 mollusca, wnich have their organs contained in an often shapeless envelope, and 

 which even present no traces of solid organs. 



The author had already shewn that every vertebra or vertebral apparatus is 

 originally composed of nine elementary pieces, to which he gave tlie names of 

 basial, costaux, polergaux, arthromeraux and arthroceraux. He had also an- 

 nounced that the examination of the shell of molluscous animals shews that the 

 basial piece may be formed of two, and that there may thus be five pairs of ele- 

 mentary pieces. In the present investigation we therefore come to the same re- 

 sults as in the researches respecting the vertebra of the articulated animals. But 

 as in the external world, the vertebra of a molluscous animal performs no other 

 office than that of containing and protecting the body of the animal, there results 

 that none of these elements could have been broken or fractured, and that they 

 even incessantly tend to fonn a whole, a homogeneous aggregate, of which it 

 would be very difficult to trace and mark out tl)e rudimentary pieces. The 

 functions performed by the pieces of the vertebra in the molluscous animals dif- 

 fer entirely from those whicli they perform in the vertebrate and articulated ani- • 

 mals ; and therefore these pieces ought, in strictness, to receive different names. 

 It being, however, of more importance, in the present state of science, to specify 



