432 D. J. SCOURFIELD, SYNOPSIS OF THE KNOWN SPECIES OF 



localities from which they have been obtained will also be given, 

 and the general distribution of all the species, so far as known, 

 will be shown in tabular form. 



Of the ninety-six species recorded from Sweden, w^e have, it will 

 be seen, only seventy -five, thus showing that there is a considerable 

 amount of work yet to be done even in the matter of discovering 

 species " new to Britain," although we can never expect, of course, 

 to find all the Swedish species in the British Isles, as some of them 

 are typically Arctic forms. On the other hand, we have, in 

 addition to the seventy-five species just mentioned, six which 

 are not given by Lilljeborg as Swedish, thus bringing up the 

 British total to eighty-one. The number of species recorded by 

 Lilljeborg is much smaller than it would have been if he had 

 followed the example of some other authors in i-ega,rd to the validity 

 of certain so-called species ; but I believe he is quite right, as a 

 rule, in putting together again many of the forms that have . 

 been dignified with specific names. We necessarily have many 

 of these varieties in this country, and some of them will be duly 

 noticed. 



It is intended, in a subsequent paper, or series of papers, to 

 extend this summary of the known British fresh-water species 

 to the other Orders of Entomostraca, and I shall be glad to 

 receive any information as to supposed new British species, or 

 any records of distribution. 



CLADOCERA. 



SiDIDAE. 



Sida Straus. 

 S. crystallina (0. F. Mliller). 



A very widely distributed species though somewhat sporadic in 

 its occurrence. 



Diaphanosoma Fischer. 

 D. brachyurum (Lievin). 



Daphnella Wingii Baird (in part) (1).* 



iJajohnella hrachijura Beck (3), Pratt (18), Scott (20, 21, 23). 

 Diaphanosoma hrandtianum Scourfield (29). 

 A fairly common form in clear water all over the British Isles. 



* The numbers in brackets refer to the fist of literature at the end of 

 the paper. 



