i'. .1. scdl KKIKLI) (I.N i;\I'O.M(»s||;A(A. If))] 



possibly- be due to the fact that sufficient attention was not 

 given to the collection of bottom-sediment, in which many 

 species of this order habitually occur, but it must also be noted 

 that some of the forms included in the complete British list, 

 although occasionally found in fresh-w^ater, are more typically 

 brackish-water animals, and ought scarcely to be put in 

 comparison with those from Wanstead Park. 



A second result, arising incidentally from the effort to make 

 as complete a list as possible, is that one new species has been 

 found, and a few others added to the British fauna. The new 

 species belongs to the genus Cancloua, and is considered by 

 Prof. G. S. Brady to be quite distinct from all those previously 

 known. He has provisionally given it the name of Candona 

 ahhreviata, and has undertaken to describe it. This will pro- 

 bably' be done in an appendix to the Monograph of the Ostra- 

 coda of the North Atlantic and North- Western Europe, a 

 second portion of which is in preparation by Prof. Brady and 

 the Rev. A. M. Norman. The other species alluded to as 

 having been added to our Entomostracan fauna are Cerio- 

 daphnia megops, G. quadrangula, Baphnia galeata, and Alona 

 intermedia. They have already- been described before this 

 Society {ante^ pp. 63-69, Plates IV. and V.). and it need only 

 be added that although subsequently found in. other districts, 

 Wanstead Park was the first place from which these forms 

 were taken. 



An examination of the first two Tables appended wiW show 

 that another result has been to obtain some useful evidence as 

 to the periodicity of many species. This periodicity, although 

 well knowai among the Cladocera, is not, so far as I am aware, 

 usually recognized as occurring among the Ostracoda and 

 Copepoda. The data furnished by this record, therefore, may 

 have some value in suggesting unsuspected powers of repro- 

 duction in the latter orders, while even in the case of the 

 Cladocera, some additional light may possibly be thrown upon 

 the limits of the active and resting periods in different species. 

 I do not pretend to say that the periods of activity' found to 

 hold good in these cases at Wanstead Park would be exactly 

 matched in other districts ; indeed, I have many facts to the 

 contrary, and on purely a priori grounds it is scarcely likely 

 that this precif;e agreement should exist. Nevertheless, the 



