1904 - 5 .] Free- Swimming Crustacea of Firth of Clyde. 805 
Cladocera were not very numerous in the gatherings under con- 
sideration. Evadne Nordmanni was observed in those collected 
in April and May and in three of the September samples. The 
two species of Podon differed in their distribution in rather a 
marked way, Podon intermedius being present in three of the 
September gatherings, but absent in those collected in April and 
May ; while P. Leuekarti was present in the two earlier gatherings, 
but was absent in all those collected in September. 
It will be observed from these remarks on the various species, and 
also from the tables referred to, that there is a tendency for the 
distribution of several of the more common of the free-swimming 
Copepoda to be influenced by the seasonal changes that take place 
throughout the year. But without a study over a lengthened 
period of these seasonal changes, and of their effect on the dis- 
tribution of marine organisms, the results obtained will be 
incomplete. 
{Issued separately July 7 , 1905 . ) 
