286 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
Port Erin are:—1,000 on July 18th, 57,000 on 
July 22nd, 10,000 on July 26th, 8,000 on July 29th, 
(few in August), 57,000 on September 16th (and 25,000 
in another net), 8,000 on September 17th, 8,000 on 
September 29th. The highest number in October is 
6,000, in November 2,000, and in December 400. 
We shall now take out a few of the more prominent 
of the Metazoa from the bay gatherings throughout the 
year, and consider them separately. 
SAGITTA. 
We discussed this type so fully last year (Part III, 
p. 241) that a few words now to bring the record 
up to date will suffice. The results for 1910 agree closely 
with those for previous years. Again the chief 
maximum is 1n summer, extending over June, July and 
part of August, and again there is a second but much 
smaller increase in numbers in October. The two 
greatest hauls from the ordinary horizontal nets were 
obtained in the bay on July 4th (1,015 specimens) and 
on August 5th (1,138 specimens). In a haul of the 
shear-net on August 8th at Station I, five miles off land, 
3,200 Sagitta were obtained. 
According to some planktologists, Sagitta is an 
oceanic organism. In our view it would be better to 
regard this and some other forms as ‘‘ panthalassic ’’ 
rather than oceanic, since they occur as freely in coastal 
waters as in the open sea, and their appearance in the 
in-shore plankton mixed with neritic forms cannot be 
regarded as an invasion due to an influx of oceanic water. 
Sagitta is present in Port Erin Bay all the year round. 
It was only absent from our bay hauls on two days, one 
in January and one in September, and it reproduces in 
the coastal waters. 
