ON BOSMINTD.E, MACB.OTHRICIDJE, ETC. 889 



Peracantha brevirostris, the title of which conveys the chief cha- 

 racter by which he would distinguish it from P. truncata. The 

 male of the latter species differs from the female in a similar 

 manner, the rostrum being shorter, and the superior antenna? 

 extended further beyond it. 



14. Lynceus LiEvis, (G. 0. Sars). PI. XVIII, fig. 5; and 

 PI. XXI, fig. 14. 



1844. Lynceus trigonellus, Zaddach. Synopsis Crust. Pruss. 

 Prod., p. 28 (but not of other authors). 



1858. Pleuroxus ornatus, Schoedler. Die Branchiop. der Umg. 

 von Berlin. 1 Beitrag, p. 28 {name only, no description 

 or figure). 



1861. Pleuroxus l&vis, G. 0. Sars. Om de i Omeg. af Christ. 



forekom. Cladocerer, p. 22. 



1862. Pleuroxus hastatus, Gr. 0. Sars. Om de i Omeg. af 



Christ, forekom. Cladocerer. Andet Bidrag., p. 52. 



1862. Pleuroxus ornatus, Schoedler. Die Lynceiden uPolyphc- 



miden d. Umgegend von Berlin (Jahresbericht der Do- 

 rotheenst. Bealschule), p. 25. PL II, fig. 32. 



1863. Pleuroxus ornatus, Schoedler. Neue Beitrage zur Xatur- 



geschichte der Cladoceren, p. 47. PI. II, fig. 32. 



Carapace long, ovate, posterior extremity narrow, truncate, 

 only very slightly oblique ; dorsal margin boldly arched from 

 the end of rostrum to the junction with the posterior extremity ; 

 ventral margin ciliated throughout, anteriorly very convex, me- 

 dially sinuate, posteriorly receding towards dorsal margin, infero- 

 posterior angle produced downwards into a small spine-like point, 

 no teeth ; surface punctate and obscurely reticulated, reticula- 

 tions hexagonal. Head produced into a long, acute rostrum, 

 which is projected nearly horizontally. Eye-spot half the size 

 of the eye, and much nearer to it than to the end of the rostrum ; 

 anterior antennae much shorter than the rostrum; posterior an- 

 tennas very short. Abdomen narrowing gradually towards the 

 claws, superior margin with a slight sinus anterior to the row 



