ON BOSMINID.E, MACROTHRICIDiE, ETC. 391 



smooth or only slightly punctate over the greater part of the 

 figure. In some of our examples it is not to he seen at all ; and 

 where present is more obvious on the central and dorsal portion 

 of the carapace, while the punctation is more evident towards 

 the ventral margin. 



First found by one of us (G. S. B.) in Crag Lough, Northum- 

 berland, and subsequently at "Hell Kettles," near Darlington. 

 On the Continent it is known to inhabit Prussia and Norway. 



15. Lynceus teigonelltjs, Mutter. PL XXI, fig. 11. 



1776. Lynceus trigonellus, Midler. Zool. Dan. Prod., No. 2395. 



1820. Lynceus aduncus, Jurine. Histoire des Monocles, p. 152. 



PL XY, figs. 8, 9. 

 1848. Lynceus trigonellus, Lievin. Die Branchiopoden der Dan- 



ziger Gegend, p. 41. PL X, fig. 4. 

 1850. J. Pleuroxus trigonellus, Baird. Brit. Entomos., p. 134. 



PL XYII, fig. 3, the female. 



1850. $. Pleuroxus hamatus, Baird. Brit. Entomos., p. 136. 



PL XYII, fig. 5, the male. 



1851. Lynceus aculeatus, Eischer. Mem. presentes a 1' Acade- 



mie Imp. des Sciences de St. Petersbourg, par divers 



Savants, p. 192. PL X, figs. 1, 2. 

 1853. Lynceus trigonellus, Lilljeborg. De Crust, ex Ord. tribus 



Clad. Ostrac. et Copep., p. 80. VI. IX, fig. 1. 

 1860. Lynceus trigonellus, Leydig. Naturges. der Daphnideu, 



p. 223. 

 1863. Pleuroxus trigonellus, Schoedler. Neue Beitrage zur 



Naturges. der Cladoceren, p. 44. PL II, figs. 33-36. 



1863. Pleuroxus aduncus and Bairdii, Schoedler, 1. c, p. 46 

 and 50. 



Carapace subovate, much wider in front than at the posterior 

 extremity, which is obliquely truncate ; dorsal margin strongly 

 arched ; ventral flexuous, finely denticulated on the edge of the 

 anterior portion ; fringed with long cilia ; infero-posteal angle 

 not produced, furnished with two or three minute teeth ; surface 



