MODERN SYSTEMS. 297 



gi-ther, naturalists make again the same mistake which 



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Cuvier committed, \vheii he associated the Helminths 

 with the Kadiates, only in another way and upon a 

 greater scale. 1 The Bryozoa are as it were depauperated 

 Mollusks, as Aphanes and Alchemilla are depauperated 

 Eosaceee. Eotifera are in the same sense the lowest 

 Crustacea ; while Helminths and Annelides constitute 

 together the lowest class of Articulata. This class is 



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connected by the closest homology with the larval states 

 of Insects ; the plan of their structure is identical, and 

 there exists between them only such structural differences 

 as constitute classes. 2 Moreover, the Helminths are 

 linked to the Annelides in the same manner as the apodal 

 larvee of Insects are to the most highly organized cater- 

 pillars. It may truly be said that the class of Worms 

 represents, in perfect animals, the embryonic states of 

 the higher Articulata. The two other classes of this 



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branch are the Crustacea and the Insects, respecting the 

 limits of which, as much has already been said above 3 as 

 it is necessary to state here. 



The classification of the branch of Articulata may, 

 therefore, stand thus : 



1st Class: Worms; with three orders, Trematods, 

 (including Cestods, Planarise, and Leeches,) Nematoids, 

 (including Acanthocephala and Gordiacei,) and An- 

 nelides. 



2nd Class : Crustacea ; with four orders, Eotifera, 

 Entomostraca, (including Cirripeds,) Tetradecapods, and 

 Decapods. 



3rd Class : Insects ; with three orders, Myriapods, 

 Arachnids, and Insects proper. 



1 Compare Chap. II, Sect. 1, p. 21 G. 3 Compare Chap. I, Sect. 18, p. 

 ' 2 Compare Chap. II, Sect. 2, p. 219. 118-120. 



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