LIST OF DUTCH ACAEI. 61 



ignotis speciebus refertum , eorunique nomina specifica in novellis 

 Danicis, Germanicis et Gallicis, ut Entomologis stimulum novi 

 cognoscendi generis excitarem , puhlici iuris feci; Hydrachnas dixi 

 seu araneas aquaticas, quia araneas et acaros terrestres maxime 

 referunt , in aquis tarnen semper degunt. » 



And again p. IX: 



«Ipse numerum Hydrachnarum quadragenari urn anno 1769 

 nominibus specificis in publicum prolatum aliis negotiis, observa- 

 tionibus praesertim rei herbariae, animaliumque marinorum et 

 intestinalium distractus, septem tantam augere potui». 



I mention this fact, because I nowhere met with it. Even in the 

 papers of Scandinavian authors I never found a citation of Müller's 

 List of 1769. Müller sent a copy of his list to de Geer, but 

 apparently de Geer did not give much attention to it. We read 

 viz. in Müller's above mentioned work p. XXX : in the paragraph 

 on Hydrachna buccinator {Acarus caudatus de Geer.) : ■ 



(( Nomine triviali caudatmn minus bene suum dixit Acarum 

 immortalis & de Enlomologia optima meritus de Geer, cum ex enu- 

 meratione Hydrachnarum 1769 edita, eique missa , plures cauda- 

 tarum species dani scire potuerit. » 



Indeed a very fair but severe reproach ! 



The Scandinavian waters are abundant in water-mites, as we 

 learn from writers of this century. The more remarkable is the 

 fact that Linné, who has so well known the most common water 

 hexapods did not met with the brigt coloui'ed Hydrachnids. 

 Müller too wonders at the fact , p. VI : 



« Mirandum sane , Linnaeum , tanto discipulorum numero stipa- 

 tura, nullam omnino noscere Hydrachnam; viderunt certe, cuique 

 enim aquas palustres inspicienti oberrant at nomine acari aquatici ^ 

 et genere et specie ab omnibus Hydrachnis diversi, atque confusis 

 Linnaei synonymis obfuscati , banc gentem , uti Planarias nomine 

 Fasciolae hepaticae derelictui habuerunt, mihiqui abundantem ani- 

 malculorum messe m reliquerunt. His tamen collectis, singulatim 

 dispositis , ac pubhce indicatis , cur tamen ignorare persistant j 

 nostrae non est indaginis». 



