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



was probably obtained by counting some of the little setae 

 which clothe the sides and lower margin of the post-abdomen. 

 The accompanying drawings were made from one of Professor 

 Brady's specimens (see PI. 24, Figs. 1, 2, 3, and 4). 



Only found in one locality, namely, in a roadside pond near 

 Staithes, Yorkshire. 



D. psittacea Baird (1). 



The species described by Baird as B. j^sittacea has never again 

 been certainly seen by any collector of British Entomostraca^ 

 but a form thought to be the same, and called by this name has 

 been found occasionally on the Continent. Lilljeborg figures and 

 describes this, although he does not record it as Swedish. From 

 Baird's figure, I should have thought that D. psittacea was the 

 same as D. atkinsoni, if both had not been described by Baird. 

 himself. 



D. pulex (De Geer). 



We have many varieties of this common species, some of whicb 

 liave been recorded by Prof. Brady and others under the names 

 of D. schoedleri, D. hrevispina, D. hamata, D. obtusa, and D. 

 propinqua. I am rather inclined to think that at least D. obtusa 

 (including B. propinqua) should be regarded as a good species. 



D. longispina 0. F. M tiller. 



D. pulex var. longispina Baii'd (1). 



Several varieties of this species have been placed on record 

 by Brady (5). 



D. hyalina Ley dig. 



?i>. jardinii Baird (2).* 



D. lacustris, D. galeata, D. hyalina Brady (5), Scourfield 



(25, 29). 

 D. jardinii Brady (4), Scott (20). 



Four subspecies are recognised by Lilljeborg, and three of 



* As it seems impossible to decide whether Baird's D. jardhiii was a 

 pointed-headed form of D. Jiyalina or B. cucnllata, it will probably be 

 better to drop the earlier name altogether, as is done by Lilljeborg. 



