= 
1902-1903.| Dzstribution of the Smaller Crustacea. 6) 
to our shores by a more than usual southward trend of cold 
water from the North Atlantic. The following examples will 
illustrate this migration of sub-arctic and arctic forms. 
Thalestris krohniv (Kroyer) (=Thalestris serrulatus of Brady’s 
Monograph) is a free-swimming arctic copepod, of a brick-red 
colour when living. This copepod has been recorded from 
various parts of the Arctic Sea, off the coasts of Finmark, and 
between Novaya Zemlia and Spitzbergen and elsewhere. 
But though a decidedly northern species, it sometimes makes 
its way far to the southward. Dr Brady, in his ‘ Monograph 
of the British Copepoda,’ records its occurrence at the Scilly 
Isles (1880); I. C. Thompson obtained it near Puffin Island 
(Irish Sea) in-1889; and in 1890 I reported its occurrence 
in the Firth of Forth and in Dornoch Firth. My son has 
also obtained it in a surface gathering from the Gulf of St 
Lawrence. In all these instances, however, so far as known 
to me, it occurred very sparingly. 
The next species I would refer to is the amphipod 
Luthemisto compressa (Goes). In 1892 an immense shoal of 
Huthemisto compressa was observed off the Yorkshire coast. 
The sea was described as literally alive with them, and great 
numbers were afterwards washed ashore by sea-winds, and 
afforded a feast for starlings and other frequenters of the 
tidal line (see T. H. Nelson in the ‘ Naturalist’ for May 
1892). Some of the specimens made their way into the 
Firth of Forth, and were captured in the tow-nets of the 
fishery steamer which was at that time in the Forth estuary, 
being mentioned among the “records” for that year. This 
species is not uncommon in the Arctic seas. It is interesting 
to notice that in 1891 and 1892 there was also a considerable 
increase in the numbers of Parathemisto oblivia (Kroyer) taken 
by our tow-nets. The greatest increase inside the estuary 
occurred in 1891, while at the mouth of the estuary the 
greatest increase observed was in 1892. The cause of this 
remarkable southward migration of Euthemisto compressa along 
eur east coast might be due to an unusual southerly move- 
ment of cold water from the North Atlantic. No similar 
migration has been observed in recent years. . 
In 1893 I reported the occurrence of the sub-arctic 
amphipod Anonyx nugax (Phipps) in the vicinity of May 
