228 SUPPLI'.MENT 



As we have thus touched, however slightly, on the history 

 of the classifications of Crustacea, it would be highly improper 

 to pass over in silence the name of our distinguished country- 

 man Dr. Leach. His labours on certain parts of this order 

 are highly valuable, and at once excite our regret at their un- 

 happy interruption, and our earnest hope of their auspicious 

 recommencement and com]:)letion. The nature of our work 

 will not permit us to follow all his details, or give a minute 

 analysis of his distribution. His generic divisions are gene- 

 rally noticed in our text, and nothing important in his re- 

 searches shall be omitted in these supplementary additions. 



Although the name oi Crustacea has become one of general 

 usage, we may yet consider that of malacostraca, as in some 

 measure, if not altogether synonymous, although the latter has 

 been used by M, Latreille and other recent writers, to indicate 

 a single division of the class, in which those beings are com- 

 prehended. The term /.ictXaicoaTpaKoe (molli crusta obtectus) 

 designated, among the Greeks, those marine animals without 

 blood, whose external envelope, much less solid than the testa 

 of the shelled moUusca, is yet considerably more so than the 

 skin of the naked mollusca. 



The Crustacea, considered under the various relations which 

 their organization presents, should incontestably occupy a 

 very elevated rank among invertebrated animals, and those 

 which are provided with articulated limbs. They cannot be 

 placed at a remote distance from the arachnida and insects, 

 whose body is like their's, symmetrical, encompassed with a 

 corneous, solid, and resisting skin, which performs the func- 

 tions of the skeleton in the animals of the superior classes ; 

 whose members are, like their's, composed of several distinct 

 pieces ; whose eyes are always apparent, and whose genera- 

 tion is bisexual. 



They are more distant from the animals of the class anne- 

 lides of Lamarck, whose bod}^ is destitute of true limbs, in 



