CRUSTACEA. 643 



abdomen ; a moveable appendage, resembling a rostrum at the 

 anterior part of the shell. Four antennae, terminated by a long 

 many-jointed seta, serving for swimming. Natatory feet bifid, in 

 different number behind four pairs of branchial feet, lamellose. 



Sp. Nebalia Herbstii, Cancer bipes 0. FABR., Faun. Groenl. fig. c, p. 246 ; 

 Nebalia Geofroy EDWARDS, Ann. des Sc. natur. Tom. xm. 1828, pp. 297 

 300, PI. xv. GUERIN Iconogr., Crust. PI. 32, fig. 2. Compare also 

 EDWARDS Ann. des Sc. not. IQ S&rie, in. pp. 300 311. To this genus 

 belongs also Monoculus rostratus MONTAGU (Transact, of the Linn. Soc. xi. 

 fig. 5), Nebalia Montagui THOMPSON. 



B. Eyes sessile. 



Limnadia BiiONGNiART. Body inclosed in a bivalve, oval, 

 compressed shell. Antennae four, anterior short, undivided, pos- 

 terior and exterior large, with a cylindrical peduncle and two 

 branches setaceous, multiarticulate. Feet (eighteen to twenty- 

 seven pairs) lamellose, bifid, with a filament at the base recurrent 

 or ascending towards the back. Last segment of body terminated 

 by two diverging filaments. 



Sp. Limnadia Hermanni AD. BRONGNIART, Mem. du Mus. vi. 1820, pp. 83 

 92, Daphnia gigas HERM., Mem. apterol. Tab. V. figs. 4, 5, KOCH in 

 HEKRICH-SCH^PFER Deutsckl. Ins. Heft 185, Tab. 10 ; Limn, mauritiana 

 GUERIN, Magas. Zool. 1837, Cl. vn. PL 21, figs, i u, Iconogr., Crust. 

 PI. 33, fig. 2. 



Compare also J. KRYNICKI, Des Limnadies in the Bullet, de la Soc. imp. 

 des Natural. deMoscou, n. 1830, pp. 173 182, PL vn. Limnadia tetracera. 

 This writer found males, and observed the copulation. BRONGNIART 

 observed only females. 



Estheria RUEPPELL. 



Sp. Estheria dahalacensis RUEPP., STRAUS DURCKHEIM, Museum Senckenber- 

 gian. n. 1837, pp. 117 128, Tab. vii. 



Apus SCH.EFF., Limulus MUELL., LAM. Shell produced from 



head over thorax and a great part of abdomen, clypeiform, thin, 



leeply emarginate posteriorly. Eyes two, approximate, including 



\n ocelliform point. Two inferior antennae very short, styliform, 



jiarticulate. Mandibles strong, gibbous externally, with internal 



; margin straight, denticulate. Two pairs of maxillae. Sixty pairs 



, i)f feet ; first pair incurved, filiform, with three very long setae 



ixsert beyond the shell, multiarticulate ; remaining feet lamellose. 



Six last segments destitute of feet ; two setae at the last segment 



long, multiarticulate. 



412 



