76 MODERN SYSTEM. 



Class I. CRUSTACEA. 



History. — "All the Crustacea, as their name imports, are covered by 

 integuments composed of cnistaceous materials, more earthy than 

 those which envelo])e the Myrinpoda, the Arftchnoiden, and Insccta. The 

 greater portion of these animals live on putrid or decomposing animal 

 substances, and in all the sexes are distinct." 



To the kindness and liberality of my much respected friend Dr. 

 Leach, I am indebted for the above passage and following review (which 

 he has since published in the eleventh volume of the Dictionnaire des Sci- 

 ences Aatu?-elles) of the rise and progress of Crustacea ; which is selected 

 from his valuable manuscripts. 



" The ancients were well acquainted with the Malacostraca {MaXa- 

 v.0(j7pa.K0i), which they placed between the Mollusca and Fishes. Ari- 

 stotle has dedicated a chapter to the species known to him : Athenjeus 

 has emunerated those used as food; and Hippocrates has made mention 

 of such species as were considered to be useful in medicine. To the 

 observations of Aristotle very little was atided by Pliny; and from his 

 time until that of Rondeletius, Belon, Gesner, Aldrovandus and John- 

 son, (who likewise placed them between the Mollusca and Fishes,) lit- 

 tle or nothing was done that tends in any way to illustrate their natural 

 history or structure. Linnc, in the first (1735) and subsequent editions 

 of his Systcma Xatune, placed all the Crustacea amongst the apterous 

 insects, in the genera Monoculus, Cancer, and Ouiscus. 



" The Ci-ustacca were arranged by Brisson (Regnum Animale) along 

 ■with the IShjriapoda and Arnchn'uidea, being placed between the Fishes 

 and Insects, under the Class Crustacea. 



" Fabricius in his Sijstcma Eutomologia: (1775) distributed "these ani- 

 mals into two Classes: 1, Syngnatha, comprehending 3/oHOt7</«s and 

 Oniscus, which he associated with Ephewera, Phri/ganca, Fodnra, Tcn^ 

 thredo, and other genuine Insects: 2. Agonata, containing Cancer, Pa- 

 gurus, Scyltai'vs, Astacus, and Gammarus, to wbich he also added Scorpio. 

 The same author in his .S'/xr/cs (1781) and ^fantissa Insccforum (1787) 

 maintained the same general distribution; adding in the former of those 

 works tlie genus Squilla, and in the latter Ilippa, removing in each 

 work the genus Scorpio from the Agonafa. In the second volume of 

 his Entonwlogia Syslematicu (1793) his class Si/iignatha contained only 

 genuine Insects, the Onisci being removed to a new division named Mi- 

 tosaiu, where they were associated with tbe Mi/riapoda ; the rest he still 

 placed with the Agonala, to which he added the gonus Limulus, Cymo- 

 thoa and Galathca. 



"Latreillein his Pmv.s des Caractcres drs Tusectcs (1796) (a Mork 

 which commences a new ara in the science of Entomology, and in 

 which, for the first time, the distribution of Insects into families is in- 

 dicated), considered tlic Crustacea as forming three Classes or Ordcr.>5 



