86 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
circumstances permitted throughout the year. These were 
greatly augmented by the special collections taken by Professor 
Herdman from his motor launch working in the Bay itself, and, 
occasionally, as far as two and three miles outside it, during 
the University vacations at Haster and Midsummer. The 
outside collections were not very numerous, but they help to 
indicate how the eggs were distributed. 
There is no easy and rapid method for working through 
a sample of plankton containing fish eggs. The work can be 
facilitated to some extent by washing the collection through 
a series of three sieves. The first one should be of brass wire, 
12 meshes to the inch, which allows everything, except sagitta, 
crab megalopa and other larger forms, to pass through. The 
intermediate sieve is of silk, of 36 meshes to the inch. This 
retains all the fish eggs and plankton organisms down to, but 
generally excluding, anything about the size of newly hatched 
naupli of barnacles. The last sieve is also of silk, 200 meshes 
to the inch. It retains the diatoms, dinoflagellata and all the 
smaller organisms caught. The residue in the three sieves is 
turned out into flat glass dishes, similar to those used for 
bacteriological cultures, mixed with a little water and placed 
against a black background. That from the brass sieve is 
taken first, and the number of sagitta, etc., noted. It may 
contain a few fish eggs, entangled amongst the larger things. 
The eggs of the long rough dab and the plaice sometimes just 
fail to pass through the wire gauze. The residue from the 
intermediate sieve 1s next examined, and the fish eggs are 
picked out by means of a pipette. Collections taken in March 
and April frequently contain over 100 fish eggs. The residue 
from the fine sieve is also examined to make quite sure that » 
no very small eggs have escaped into it. The residue from the 
two silk sieves is afterwards transferred to graduated tubes, and 
the estimation of the organisms proceeded with in the manner 
described in the Report for 1907 (p. 97). The eggs require to be 
en 
_ a" 
