Zoological Society. S^ 



The genus Eathena at present contains three species : — k^ iiniiit 



1. Estheria gigasy the Daphnia gigas of Hermann, identical with 



the Cyzicus Bravaisii of Audouin and the Isaiira cycladoides of 



i, 2. Estheria tetracera, the Limnadia tetracera of Krynickai^ f to"^ 

 3. Estheria DahalacensiSy Straus Durckheim. . > 



To these three species I now propose adding six others, all in t^^ 



collection of the British Museum. 3,i 



,, ,, Legion BRANCHIOPODA. ^^ 



i . ni^ in;; . i Order Phyllopoda. 



J'amily LiMNADiADiE. 

 Animal almost entirely enclosed within a buckler or carapace re- 

 sembling exactly a bivalve shell. Feet all branchial ; from eighteen 

 to twenty-seven pairs in number. Antennae four pairs ; the two 

 superior used as organs of locomotion. Eyes two; closely approxi- 

 mated. ^ '.'^ .'^' 



Genus Limnadia, Brongniart. 

 , Carapace very large in proportion to the size of the animal, which 

 appears not to fill much more than half of it. Head small, and having 

 a little behind the eye a small pear-shaped body on its dorsal margin. 

 Caudal segment truncate and terminating in two diverging lamellae, 

 ciliated on their under margin. Small antennae club-shaped. Jaw 

 foHated. Carapace beautifully transparent, of a whitish colour and 

 very thin and delicate. Valves nearly quite smooth or only showing 

 two or three slight concentric ridges on their anterior margin, and 

 when highly magnified, numerous very minute dots or puncturations. 

 The animals swim on their back, and no males have ever as yet 

 been observed. 



Sp. 1. Limnadia Hermanni. 



L. Hermanni, Ad. Brongniart, M^m. du Mus. d'Hist. Nat. vi. t. 13. 

 f. 1-2, 1820. Desmarest, Consid. gen. sur les Crust. 379. t. 56. f. 1, 

 1825. Latreille, Cuv. Regn. Anim. iv. 173, 1829. Bosc, Man. d'Hist. 

 Nat. des Crust, ii. 236, 1830. Guerin, Magaz. de Zool. Class 7. t. 21 . 

 f. 12, 1837. Lamarck, An. sans Vert. 2nd edit. v. 185 (note). M. Ed- 

 wards, Hist. Nat. Crust, iii. 362. No. 1. Cuv. Regn. Anim. edit. 

 Crochard, Crustaces, t. 74. f. 1, \a. 



Carapace-valves of a rounded oval form, and permitting only the 

 terminal branches of the large antennae and the tips of the caudal 

 lamellae to pass beyond their margins ; antennules of the length of the 

 peduncles of the large antennae, club-shaped and crenulated on their 

 upper edge ; large antennae nearly half as long as the body, and having 

 in each branch 12 joints ; feet 22 pairs in number ; caudal lamellae of 

 considerable length ; carapace of a clear transparent white colour, and 

 nearly quite smooth on its surface. On the anterior half we see two 

 or three concentric striae or rather delicate ridges running parallel 

 with the lower margin, and when examined by a microscope of con- 

 siderable power, we can detect the whole surface of the valves covered 

 with numerous minute dots or puncturations. These do not appear 



