SEA-FISHERIES LABORATORY. 291 
PsrvupocaLanus.—P. elongatus comes next after 
Oithona similis as one of the most abundant of Copepoda 
in our district. It is present in our nets all the year 
round, and reaches thousands per haul in every month 
except February and March. It begins with 1,200 and 
then 1,600 in January, dwindles to units, tens and a few 
hundreds in February and March, reaches 6,000 and 
then 12,000 in April, remains at from 1,000 to 6,000 
during May, 13,000 on June 24th, 12,500 on July 11th, 
20,000 on August 8th, 26,800 on September 8th, up to 
9,000 in October, 4,000 in November, and 5,000 on 
December 5th. Thus there seems to be a first maximum 
in April, and a second much greater one in August and 
September. The course of the species throughout the 
year corroborates that given for 1909, but the numbers 
are now larger. 
OrrHona.—O. similis is by far the most abundant 
Copepod in this part of the Irish Sea. Its numbers 
average double those of any other species. April is the 
only month where the numbers do not reach 1,000, and 
there is a well marked maximum of 126,000 on 
August 20th. Other high numbers were 83,000 in June, 
49,000 in July, and 48,000 in September—higher 
numbers again than in previous years, although the same 
course through the year was preserved. ‘There is an 
extended maximum in June, July, August and 
September. 
Temora.—T. longicornis, unlike the last species, is 
absent during a large part of the year, and, in fact, only 
reaches thousands in April to September inclusive. Its 
maximum is 33,000 at the end of July. 
PaRACaLANuS.—P. parvus is also a species that is 
present during a part only of the year. In fact, it is 
abundant only in autumn and winter. It is rare in 
