I). J. SCOUUFIEliD ON RNTOMOSTRACA. 169 



evidence of gradual changes in the Entomostracan fauna. But 

 the results have been very unsatisfactory, notwithstanding the 

 fact that a few species have been found to be restricted to single 

 ponds. I think the most that can profitably be given here is a 

 comparison of the total number of species found in each of the 

 principal pieces of water. This is shown as follows : — 



It wdll be seen, therefore, that the " Perch Pond" — probably 

 the deepest of all — is decidedly the best. 



In the following detailed list of the Entomostraca of 

 Wanstead Park, some indication has been given of the places 

 where figures and descriptions of the species can be found 

 among British publications. Advantage has also been taken of 

 the opportunity to insert a few odd notes that could not 

 conveniently be given elsewhere. 



Cladocera. 



Sida crystallma, 0. F. Miiller (Baird, Nat. Hist. Brit. Ent.,t 

 p. 107, Tab. xii., Figs. 3-4, and Tab. xiii.). This species is con- 

 fined, so far as I can discover, to the " Shoulder of Mutton 

 Pond " and the little pond receiving its surplus water. 



Daphnella brachyura, Lievin (Baphnella Wingii^ Baird, Nat. 

 Hist. Brit. Ent., p. 109, Tab. xiv.). This clear water loving 

 species finds its most congenial abode in the " Perch Pond," 

 although it is sometimes met with in other ponds. I first 

 found it in " The Lake " in 1889, but it has not been seen there 

 since the choking-up of that piece of water by Anacliaris 

 in 1890. 



Geriodaphnia megops, G. O. Sars (? Dap'hiia reticulata in part, 



* These ponds may be identified from the map in Buxton's " Epping 

 Forest," already mentioned. 



t "The Natural History of the British Entomostraca," by W. Baird, 

 Ray Society, 1850. 



