EEPOirr OF THE COUNCIL. 497 



with a single reversing thermometer, and these instruments ought to 

 be used in pairs, owing to their liability occasionally to give incorrect 

 readings. 



Samples of Plankton have been taken as usual on the quarterly 

 cruises, and also at fortnightly periods on light-vessels on the southern 

 and western coasts, and by the s.s. Devonia midway between Plymouth 

 and the Channel Islands. Weekly samples have been taken at 

 Plymouth. 



The records of species caught on the quarterly cruises are published 

 in the Bulletins of the International Council. 



Zooplankton was very abundant in May, August, and November, in 

 the Bristol Channel and around the Scillies. During May, Pseudo- 

 calanus preponderated in the samples from this region. In August 

 and November, Calanus was present in greater quantity at the western 

 stations. 



A new species of Tintinnus, which first appeared at E. 20 (oft' Start 

 Point) in November, 1907, was found occasionally during May, August, 

 and November, 1908, at isolated points from S.W. of Milford, through 

 the English Channel, to the eastern stations, while a few specimens 

 were taken in a netting from Longsands, in the North Sea, during 

 August. 



Noctiluca appeared off Milford in May, 1908, and was abundant in 

 the Bristol Channel in August. It gradually spread eastward during 

 November, and has been found very thickly distributed in the mouth 

 of the Channel and at Plymoutli during February and May, 1909. 



During the year no less than five species of Ceratium, characteristic 

 of warm seas, have been taken as far east as the Casquets area. Four 

 were taken in February, 1908, west of Ushant, In May, one of these 

 species dropped out and another appeared in its place. Two were 

 taken in August and four in November. One species appeared off' 

 Milford in November. 



Observations have been made on the food of Noctiluca, and records 

 kept of the diatoms found in them at various times. 



