430 REPORT OF THE COUNCIL. 



35'2 7oo S. running across Channel south of the Start. The saltest 

 water, 35'4 7oo S., was found at Station 4 (see above) and extended 

 north-east nearly to Station 2 (47 miles S.W. of the Eddystone). 

 As usual, a southerly current of comparatively fresh water from the 

 Irish Sea was found reaching nearly to the mid-channel line south of 

 the Scilly Islands. During March the salinity of the western half of 

 the Channel fell, and that of the eastern part rose, reaching 35"4 on 

 the Newhaven-Caen line in April. 



As in the previous year samples of plankton have been regularly 

 collected on the quarterly cruises, and as far as practicable in the 

 intervals between the cruises. The records of the species found on 

 each cruise are published in the Bulletin of the International Council. 



A paper by Dr. Gough on the distribution and migrations of the 

 Siphonophore, Muggicea atlantica, in 1904, has also been published by 

 the International Council. From this paper it appears that a shoal of 

 Muggirea entered the English Channel in April from the south-west, 

 the species being first observed off Usliant. It then spread eastward 

 into the Channel as far as Portland, where it was found in August, and 

 also northwards, being taken off the Land's End in the beginning of 

 June. It was found in the Irish Sea in August, and subsequently 

 along the south coast of Ireland as far west as Fastnet, and on the 

 west coast as far north as Galway Bay. 



The plankton during the summer and autumn of 1905 was char- 

 acterized by the appearance in the English Channel of a vast swarm of 

 Pteropods, Limacina retroversa, Fleming. These Pteropods were first 

 observed on the south coast of Ireland and entered the Channel from 

 the north-west. They thus appeared to spread in a direction opposite 

 to that taken by Muggicea in the preceding year. Limacina retroversa 

 is a species which is seldom met with in the Cliannel, being more com- 

 monly found in more northern waters. Its appearance in the Channel 

 is therefore of interest, as it suggests a liow of water from a more 

 northerly direction than usual, a suggestion which is supported by the 

 results of the hydrographic work. In company with the Limacina, 

 other northerly species were observed, for example Clione limacina and 

 lihizosolenia hebetata. 



