298 Dr. J. Vosseler on the 
1. Cyclops tenuicornis, Claus. 
2. 
3. 
agilis, Koch. 
maarensts, sp. N. 
The Calanide are represented by 
4, Diaptomus castor, Jurine. 
In my Inaugural Dissertation *, like most of my prede- 
cessors, I identified D. castor, Jur., and D. cwruleus, Fisch. 
Mr. A. Poppe, of Vegesack, had the kindness to call my 
attention to my error and sent me examples of Diaptomus 
castor from which I was able to convince myself that the 
description in the above-mentioned memoir was founded upon 
Diaptomus ceruleus, Fisch., the two species being sharply 
distinguished from each other. 
In the Maar last investigated, the 
IV. PULVERMAAR, 
there were only the three species of Cyclops :— 
1. Cyclops tenuicornis, Claus. 
2. 
3. 
agilis, Koch. 
Maarensts, Sp. Ni. 
Of the three genera of Copepoda which, according to the 
foregoing statements, occur in the ‘‘ Maare,” we find :— 
1. Cyclops, with six species. 
2. Canthocamptus, with one species. 
3. Diaptomus, with three species. 
The singular mode of occurrence of Diaptomus ceruleus and 
D. castor merits special mention. ‘The former occurs usually 
in the larger accumulations of water. But hitherto | know 
of no case in which it belongs, as in the great ‘ Laacher 
See,” to the pelagic fauna, nay, so far as the Cupepoda are 
concerned, forms this almost exclusively. Déaptomus castor 
which, from accordant statements, rather belongs to the 
smaller stagnant waters, ventures, however, in the “ Holz- 
* “Die freilebenden Copepoden Wiirttembergs und angrenzender 
Gegenden ” (Jahreshefte d. Vereins fiir vaterl. Naturkunde in Wurttem- 
berg, 1886, p. 167). 
