338 CRUSTACEA OF NORTHUMBERLAND AND DURHAM 



Peracantha truncata (O. F. Miiller). 



1903. Peratacantha truncata, Lilljeborg, I.e., p. 522, 

 pi. Ixxiii., figs. 1-20. 



Lilljeborg has changed Peracantha into the more classical 

 form Pei-atacanta, but if changes like this were allowed to be 

 made where would they stop ! 



Greenley and Crag lakes, Northumberland, and Wynyard 

 and Hardwick (Sedgefield) lakes, and a pond at Bishop 

 Middleham (A. M. N.) ; Ryton-on-Tyne, Cleadon Farin pond, 

 and Axwell Park (G. S. B.) N.D. 



Pleuroxus L.EVIS G. O. Sars. 



1861. Lynceus Icevis, Norman and Brady, I.e., p. 389, 



pi. xviii., fig. 5, and pi. xxi., fig. 14. 

 1 90 1. Pleu7'oxus lavis, Lilljeborg, I.e., p. 529, pi. Ixxiii., 

 figs. 21, 22, and pi. Ixxiv., figs. 1-5. 

 Crag Lake, Northumberland, and Hell Kettles, near 

 Darlington (G. S. B.) N.D. 



Pleuroxus aduncus (Jurine). 



1867. Lynceus tn'gofielhis, Norman and Brady, I.e., p. 391, 



pi. xxi., fig. II. 

 1901. Lynceus aduncus, Lilljeborg, I.e., p. 541, pi. Ixxv., 



figs. 11-17. 



Crag Lake, Holy Island, Hardwick Lake Sedgefield (A.M.N.) 



N.D. 

 Pleuroxus trigonellus (O. F. Miiller). 



1863. Pleuroxus trigonelhis, Schodler, Neue Beit. z. 



Naturgesch. d. Cladoceren, p. 44, pi. ii., figs, 33-36. 



1863. Pleuroxus ornatus, id. ibid, p. 47, pi. ii., fig. 32. 



1874. Pleuroxus trigonellus, Kurz, Dodekas neuer 



Cladoceren, &c., p. 67 (separate copy), pi. iii., 



figs. 2-5. 



1901. Pleuroxus trigonellus, Lilljeborg, I.e., p. 534, pi. Ixxiv;, 



figs. 13-23. 



The Forge Dam,' Sedgefield (A. M. N.); pond near Sunder. 



land Cemetery, Hesleden Engine Pond near Seaham (G. S. B.) 



We question whether this and the preceding should be 



regarded as more than varieties. D. 



