ON BOSMINID.E, MACROTHEICID^I, ETC. 401 



feet, the last rudimentary. Abdomen a wide flattened blade, 

 having a beautifully serrated edge ; the serrations are portions of 

 the margin itself, and not articulated spines. Excretory orifice 

 at the end of the abdomen immediately below the terminal claws. 



Eekycerctts laiiellattts, (Ifuller). PI. XX, fig. 8. 



1844. Lynceus lamellatus, Zaddach. Synop. Crust. Pruss. Prod., 



p. 28. 

 1848. Lynceus lamellatus, Lievin. Die Branch, der Danziger 



Gegend, p. 39. PI. IX, figs. 1-9. 



1850. Eurycercus lamellatus, Baird. Brit. Entom., p. 124. 



PL XV, fig. 1. 



1851. Lynceus laticaudatus, S. Fischer. Mem. presentes a 1' 



Academie des Sciences de St. Petersbourg, Vol. VI, 

 PI. VII, figs. 4-7. 



1853. Lynceus lamellatus, Lilljeborg. De Crust, ex Orel, tribus 

 Ost. Clad, et Cop., p. 71. PI. V, figs. 7-12 ; PI. VI, 

 figs. 1-7; and PI. VII, fig. 1. 



1860. Lynceus lamellatus, Leydig. Naturges. die Daphniden, 

 p. 209. PL VII, figs. 52-56 ; and PL X, fig. 72. 



1863. Eurycercus lamellatus, and E. laticaudatus, Schoedler. 

 Xeue Beitrage zur Xaturges. der Cladoceren, p. 9. 

 PL I, fig. 28. 



Carapace somewhat quadrangular, dorsal margin well arched, 

 posterior extremity truncate and finely denticulated ; infero-pos- 

 teal angle rounded off, not furnished with any teeth ; ventral 

 margin nearly straight, ciliated. Head well rounded, rostrum 

 wide, blunt, short, rounded at the extremity ; anterior antennae 

 conspicuous, conical, tapering to the end, which terminates in 

 a circle of about eigbt spine-formed points ; posterior antenna? 

 having a spine at the end of the peduncle, all the joints of the 

 branches closely beset round their extremities with little spines ; 

 one branch with a spine on the first joint, and terminating in 

 three seta? and a spine, the other with five setae and a terminal 

 spine ; all the setae geniculate and plumose. Abdomen in the 



