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their descriptions worse than useless, we will come to Brandt, who ap- 

 pears to have caught at the true distinctive characters of form, and may 

 be said to have laid the first foundation of a perfectly natural system, in 

 his ** Conspectus Monographiae Crustaceorum Oniscodorum," published 

 in Moscow in 1833 ; and although in some instances he has stopped short 

 in his analysis, and has even mistaken the true import of some of the 

 characters, yet it must be a matter of regret that this naturalist has 

 not yet fulfilled his promise by giving to the world a full history of the 

 group. 



Milne-Edwards, who comes next in order of time, has scarcely in 

 this sustained his weU-deserved reputation in other groups, as this part 

 of his work is replete with errors of a serious nature, and the descrip- 

 tions, many of them copied verbatim from the earlier writers, and mere 

 accounts of colours, are useless. Witness the description of Fhiloscia 

 muscorum, a genus which he can scarcely have examined, or he would 

 not have proposed that it should be reunited to Oniscus, a genus from 

 which, as we shall see, it differs widely. 



In the fourth volume of the '' Memoirs of the Natural History Society 

 of Strasbourg," published in 1853, appears a paper from the pen of Pro- 

 fessor A. LerebouUet, M. D., Director of the Museum at Strasbourg, 

 entitled, '* Sur les Crustaces de la Famille des Cloportides qui habitent 

 les Environs de Strasbourg," of which it is impossible to speak in too 

 high terms, whether we regard the minuteness of details, or the author's 

 patient investigations into the labours of others, and although in one or 

 two points he has evidently fallen into error, yet, as a whole, this little 

 work must be long looked on as a standard on the subject. 



I must here also notice an excellent, but scarce little work, which 

 has but recently come into my hands, and for the perusal of which I 

 have to thank the kindness of A. H. Haliday, Esq., entitled, **Prodro- 

 mus Synopseos Crustaceorum Prussicorum," published at Konigsburg, 

 1834, from the pen of E. G. Zaddach, Ph. D., which contains much 

 useful matter; among other things, M. Edward's error concerning Phi- 

 loscia is noticed. 



Dana in his splendid work on the Crustacea, has proposed in some 

 respects a new arrangement of the group, but has, as I think, mistaken 

 in some cases the bearings of the characters, as will be shown further 

 on. 



Valuable notices of separate genera and species have appeared as 

 detached papers in some of the journals, chiefly German (as, for instance, 

 the description of the curious genus, Titanethes alhus of Schiodte (Pkce- 

 rusa alba, Koch), in Schiodte' s interesting account of the subterranean 

 Fauna of Carniola), which have thrown much light on the true affinities 

 of these animals, and render a revision of our classification necessary. 



It will be necessary to glance at the systems of classifications adopted 

 by the several authors mentioned ; but first I must notice a most elabo- 

 rate, as far as illustrations go at least, work by Henrich Schseffer, intended 

 as a supplement to Koch's ** Fauna Germanica." In this work we have 

 spurious species multiplied to a most inconvenient extent, and his ge- 



