ii6 M. J. de Giieine on the 



been met with in Scotland, at Dundee (according to Gosse, in 

 Hudson and Gosse, loc. cit. vol. ii. p. 134), and, if the identi- 

 fication above proposed be accepted, at Minnesota in the 

 United States. 



As regards the numerous forms of the genus Asplanchna 

 their geographical distribution is scarcely known. First 

 studied in Germany and in England, for a long time they 

 were noticed only in those countries ; but more recently, as 

 investigations have become more numerous, and especially as 

 the work relating to the pelagic faunas has been greatly ex- 

 tended, these Eotifera, formerly reputed rare, have seemed to 

 become more and more common. Thus, A. helvetica, dis- 

 covered in Switzerland by Imhof, exists in a great number of 

 lakes of Northern Italy, Austria, and North * and South 

 Germany. It is probable that the Asplanchnce indicated by 

 Imhof t first in Alsace and then in the harbours of Lubeck 

 and Stockholm, and by Nordqvist \ in Russia and in Finland, 

 also belong to this species. 



M. J. Richard informs me that he has taken it in great 

 numbers in several lakes of the Auvergne (Bourdouze, eleva- 

 tion 800 m. ?, and Montcineyre, 1170 ni., in the department of 

 the Puy-de-I)6me). I have collected it in abundance in the 

 Lac d'Enghien, near Paris ; lastly. Prof. Moniez sends mean 

 AspJanchna cix])\\x\'Qd^ at Lille, which also closely approaches 

 A. helvetica. It will be seen that since its discovery in France 

 by Imhof, in the lakes of Annecy and Bourget §, this Rotifer 

 has been met with at various points very distant from each 

 other. The same will certainly be the case in different 

 regions. 



I am now, thanks to the scientific zeal of my friend Charles 



* Dr. Zach arias who first met with A. helvetica in North Germany, and 

 who discovered the males of the species, appears indiued to identify it 

 ■with A. 2»'iodonta, Gosse. There is room for further investigations upon 

 this subject. To refer only to the mastax, none of those which I have 

 examined in the supposed A. helvetica seems to me to agree with the 

 figm-es and descriptions of the same part in A. priodonta. 

 ' t Imhof, " Pelagische Thiere aus Siisswasserheckeu in Elsass-Loth- 

 riugen," in Zool. Auz. 1885, p. 720 (see Annals, ser. 5, vol. xvii. p. 297), 

 and " Ueber mikroskopische pelagische Thiere aus der Ostsee," ibid, 1886, 

 p. 012. 



\ Nordqvist, " Die pelagische und Tiefsee-Fauna der grosserern fin- 

 nischeu Seen," in Zool. Anz. 1887, pp. 339 and 358. 



§ Imhof " Die pelagische Fauna und die Tiefsee-Fauna der zwei 

 Savoyei'seen ; Lac du Bourget ufi^j- Lac d'Annecy," in Zool. Anz. 1883, 

 p. 655. 



