SEA-FISHERIES LABORATORY. 285 



from 1,000 and 800 down to 100 and 50 were obtained. 

 Altogether it was found to be present in 16 bay gatherings 

 during November and December, '09. In '08 and '09, 

 Ostenfeld published papers* showing that this Indo- 

 Pacific species was noticed for the first time in European 

 waters in '03, in the Skagerrak. It was then found to be 

 present in quantity in the South-eastern part of the North 

 Sea round about Hamburg. From this it spread north- 

 wards to the coast of Jutland, and in the following year 

 appeared on the Belgian coast also. And so it remained 

 for several years. In '07 it had penetrated to the Baltic, 

 to the North of Scotland, and southwards to the entrance 

 to the Channel. The Norwegian observations show that 

 B. sinensis was present also in the sea oif Bergen in 

 the same series of years, and recent reports show that it 

 has continued in both these sea areas up to the present 

 time, in each year reaching a maximum in November and 

 the minimum in summer (May). The view is definitely 

 held by Ostenfeld that this is a case of an exotic species 

 which was introduced accidentally (e.g., by a ship from 

 the East) into European waters near the mouth of the 

 Elbe, probably in September, 1903 ; and the rate of 

 dispersal from that point is used as an indication of the 

 presence and rate of flow of currents. If Ostenfeld is 

 correct in his interpretation of the facts, then our record 

 shows that the species had extended to the centre of the 

 Irish Sea in '09, and that here, as elsewhere, it reached a 

 maximum in November (1,600 on November 13th, and 

 1,000 on November 16th, in one haul of a net for 

 15 minutes, inside the Bay). It is, however, possible 

 that we have in all these records the unusual increase of 

 a rare species which had previously escaped observation. 

 It must be remembered that during the last decade far 



* Medd. Komm. Havundersog. Plankton, I, G, 1008; and Internal. 

 Revue d. Hydrobiol. u. Hydrogr., August, 1909. 



