76 MODERN' SYSTEM. 



Class I. CRUSTACEA. 



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

 integuments composed of crustaceous materials, more earthy than 

 those which envelope the Myriapoda, the Arachiwidca, and Insecta. 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 Ibliowing review (which 

 he has since published in the eleventh votwm of the Dktionnaire des Sci- 

 ences Nalurcltcs) of the rise and progress of Crustacea; which is selected 

 from his valuable manuscripts. 



" The ancients were well acquainted with the Malaeostraca (MaAa- 

 Koo-rpaxoi), which they jilaccd between the Mollusca and Fishes. Ari- 

 stotle has dedicated a chapter to the species known to him; Athena^us 

 has enumerated 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 added by Pliny; and from his 

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

 son, (who lilcewise phiced them between the JMolJu'^ca and Fishes,) lit- 

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

 history or structvire. Linne, in the first (17.').")) and subsecpient editions 

 of his Systcma jS^ttura, placed all the Crustacea amongst the apterous 

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



" The Crustacea were arranged by Brisson {Regiunn Animale) along 

 with the Myriapoda and Arachn'Mea, being placed between the Fishes 

 and Insects, under the Class Crustacea. 



^' Fabricius in his Si/slcma Eutuwologics (1775) distributed these ani- 

 mals into two Classes: 1. Syngnatiia, comprehending Monoculus and 

 Oniscus, which he associated with Ephemera, Phrt/gunca, Fodura, Ten- 

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

 gurus, Sct/lhuus, Astacns, and Gammarus, to which he also added Sco7-pio. 

 The same author in his Species {17 ai) and Mantissa Insectorum (1787) 

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

 ■works the genus Squilla, and in the latter Hippa, removing in each 

 work the genus Scorpio jrom the Agonata. In the second volume of 

 his Enloniologia Systematica (179o) his class Si/ngnathu contained only 

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

 iosata, where they were associated with the Myriapoda ; the rest he still 

 placed with the Agonata, to which he added the genus Limnlus, Cymo- 

 thoa and Galathea. 



" Latreille in his Precis des Caractcres des Inscctes (1796) (a work 

 which commences a new a^ra in the science of Entomology, and in 

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

 dicated), considered the Crustacea as forming three Classes or Orders 



