235 



comme ches les Caryciiies. On trouve quelquefois ä leiir place une 

 ligne ou tache noiratre. Dans une espéce exotique, le Vertigo ru- 

 pestris, dont la coqiiille est longue de 5 millimetres, on ne voit 

 aucune trace de tentacules inféro-antérieurs." E. v. Maetens säger 

 i Albers Heliceen ed. 2, p. 292: "Da weder die Schale, noch die 

 Fresswerkzeuge uud der Geschlechtsapparat, soweit man sie kennt, 

 Abweichungen von Pupa zeigen, so hat die Mehrzahl der systema- 

 tiscbeu Schriftsteller sie wohl mit Recht wieder mit PiijM vereinigt, 

 bei dieseu sind ja iiberhaupt die unteren Fiihler sehr kurz. Es ist 

 dieses ein ähnlicher Fall, wie bei Acicula unter der Cionellen. 

 J. GwYN Jeffreys, som upptager si. Vertigo, yttrar (Brit. Concb. 

 I p. 253) efter anförande af djurets brist på de 2 nedre trefvarne: 

 "The shell of Vertigo differs also in a corresponding degree from 

 that of Pupa. The spire is shorter; and when the mouth is fur- 

 nished with teeth (as is commonly the case) the outer lip is con- 

 tracted. It would therefore seem to be quite as reasonable that 

 Vertigo should be separated from Pupa, as BuUmus from Helix. 

 The iine of demarcation in either case is confessedly slight. The 

 value of such generic distiuctions vnW probably not be admitted by 

 all naturalists; and unfortunately there is no Court of Science to 

 which an appeal can be made for an adjudication of the point." 

 LowELL Reeve skrifver (Brit. ]\Ioll. p. 107): "Land snails are 

 supplied with two pairs of tentacles : water snails with only one 

 pair. In the genera on the confines of these two primary divi- 

 sions, Pupa and Vertigo on the one hand, Carychium and Aiiri- 

 culn on the other. an intermediate state of these organs exists. The 

 lower tentacles lessen uutil they are reduced to rudimentary pro- 

 tuberances; finally they are represented by mere specks, and dis- 

 appear without a trace of auy kind"; p. 114: "The absence of 

 lower tentacles is not the only character in which Vertigo differs 

 from Piqja. The species are all minute. the largest Vertigo being 

 smaller than the smallest Pitpn ; and they are caracterized by the 

 distinct habit of liviug in more watery places, generally about the 

 roots of grass at the sides of lakes aud rivers, though occassionally 

 at a cousiderable elevation ou the hills " Dessa äro de vigtigaste 

 skälen för och emot antagandet af ett eget slägte Vertigo. Här 

 upptages emellertid slägtet Pupa, liksom förut sldglet Hehx. ode- 

 ladt. I Linn. Träns. XIII (1820) åtskilde Jeffreys från Pupa ett 

 genus, som han kallade A/cea, hvilket omfattade alla högervridna 

 arter af. si. Vertigo, och följande året (i Med. repos. 1821) förde 



