Tant que Ton n'a 6tudie et recueilli que les seulesCoqiiiIIes,les Testaces 

 terrestres et fluviatiles ont ete negliges, parce qu'ils offrent moins de varie- 

 tes dans les formes et moins d'eclat dans les couleurs de leurs enveloppes 

 pierreuses, que ceux qui habitent les eaux de la mer. Mais lorsque voulant 

 prendre de ces etres singuliers une connaissance un peu plus approfondie 

 et plus philosophique, on s'est mis a examiner les animaux eux-raemes, les 

 especes de terre et d'eau douce sont redevenues un objet principal d'atten- 

 tion, parce qu'il est plus facile de se les procurer avec leur animal vivant. 



Cuv. rapport essai conch. 



It will enlarge their views beyond the feverish expectancy of a precocious 

 and questionable celebrity, so easily and unworthily attainable, by the esta- 

 blishment of insulated remarkable genera; for it is only by taking up groups, 

 and thoroughly discussing them, that the progress of the science can be at 



all promoted. 



W. E. Shuckard, Cab. Cyc. Insects, p. 162. 



The genus Limneus is at present ill understood; many of the species being 

 ill defined, and no two authors, except mere copyists, agreeing which are 

 veritable species and which varieties; in fine, it may be truly designated 

 "rudis indigestaque moles." To disentangle the species, and rectify the 

 errors of authors, would, I fear, in the present state of our knowledge, 

 require greater talents and perseverance than fall to the lot of the generality 

 of mankind. Neither the influence of external circumstances, nor the 

 great differences observable in the various periods of growth, appear to 

 have been hitherto sufficiently investigated; and a correct monograph of 

 this genus would not only require the lyncean eye of a Jenyns, but the 

 searching skill of a host of less accomplished auxiliaries. 



Kenyon, Mag. Nat. Hist., vol. vii. p. 379, anno 1834. 



