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SOME ENTOMOSTRACA FROM CASTLEMILK, i fits 
Continent of Europe. Nordquist obtained it in fresh water in 
Finland, Dr. Poppe records it from North-West Germany, and 
De Guerne and Richard from Abbeville. The position of the 
little loch at Castlemilk is so far from the influence of anything 
‘like marine conditions that there can be no doubt as to the water 
there being perfectly fresh. The fact that this species can live 
under such varied conditions is of some importance in its bearing 
- on the theory of evolution, and also suggests the question as to 
whether Hurytemora clausii was originally a purely marine or a 
purely fresh-water species. 
Cyclops thomasi occurred sparingly in the material. There 
is some doubt as to its being specifically distinct from C, 
bicuspidatus, Claus. In Britain it is one of the rarer species of 
Cyclops. 
The Cyclops signatus recorded here is the form with smooth 
anterior antenne, and known as C. tenwicornis, Claus. This form 
is now regarded as the penultimate stage of C. signatus, Koch. 
Cyclops thomasi and C. signatus have both eighteen-jointed 
anterior antenne. 
Cyclops serrulatus, which has twelve-jointed anterior antenne, 
is a very common and widely distributed species, not only in 
Britain, but also on the Continent of Europe and in North 
America. 
Cyclops fimbriatus, the anterior antenne of which are only 
eight-jointed, is a small but pretty and distinct species. It has a 
fairly wide distribution, and is recorded by various European and 
American authors. 
Canthocamptus minutus is a comparatively small species, but is 
not the smillest of the fresh-water Copepoda. It usually frequents 
the vegetation at the sides and bottom of the water. Spirit- 
specimens of this and other fresh-water Harpacticide have the 
abdomen usually bent at right angles (or nearly so) to the body, 
and in this they differ from the Cyclopide. 
THE CLADOCERA. 
. The British Cladocera are nearly all confined to fresh water. 
The only marine forms hitherto observed belong to three species, 
and include the well-known Lvadne nordmanni, which may some- 
times be obtained in great numbers with the surface tow-net, and 
