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On the Pelagic Fauna of Plymouth for September, 1897. 



By 



Edward T. Browne, 



University College, London. 



IxN the Journal of this Association for 1896 (Vol. IV., No. 2, p. 168) I 

 published a few notes on the Pelagic Fauna of Plymouth for September, 

 1893 and 1895. This year (1897) I again occupied a table in the 

 Laboratory during September for the study of medusae, and also made 

 a few entries in my notebook on the occurrence of certain animals 

 belonging to other groups, and kept a special look-out for the animals 

 which I noted in previous years. Unfortunately I was not able to visit 

 Plymouth during September in 1894 and 1896, consequently the record 

 is broken by two blank years, and spoilt for an accurate comparison of 

 one year with another, but it shows that more Atlantic forms were 

 present in 1895 than in 1893 or 1897. 



The pelagic animals of the Plymouth district may be conveniently 

 divided into two sets : — 



1. Local forms, to which belong the larval stages of animals living 

 on the bottom, and the medusae liberated from Hydroids. 



2. Atlantic forms, which come up the Channel. 



It is the latter set which produces the great yearly changes in the 

 fauna, and which gives the greatest interest to pelagic work. 



The Atlantic forms often arrive suddenly, occasionally in great 

 shoals, like Thalia in June, 1893, and Doliolum in 1895, but usually 

 they are rather scarce in numbers. 



It is in the neighbourhood of the Eddystone, where the main Channel 

 tide runs, that the richest tow-nettings are taken, and I have noticed 

 that there is a difference between the fauna off the Eddystone and in 

 the Sound. On certain days I was able to obtain tow-nettings from the 

 Sound in the morning and from the Eddystone in the afternoon ; the 

 results were in favour of the Eddystone tow-nettings, both in quality 

 and quantity. 



