54 Zoological Society. 



raised, but as if they were mere opacities in the otherwise clear 

 transparent shell. 



Hab. Fontainebleau. British Museum ; sent to Dr. Leach by 

 M. Brongniart. 



Sp. 2. LiMNADIA MaURITIANA. 



L. Mauritiana, Guerin, Mag. de Zool. Class 7. t. 21. f. 1-11, 

 1837; Iconogr. Regn. Anim. Cuv. t. 33. f. 2. M. Edwards, Hist. 

 Nat. Crust, iii. 363. No. 2. t. 35. f. 7-8. Burmeister, Organiz. of 

 Trilobites, Ray edit. t. 6. f. 1.5. 



Carapace-valves of an oval shape, slightly pointed at the extre- 

 mities ; antennules club-shaped, not crenulated on the upper edge, 

 and considerably shorter than in preceding species, and the branches 

 composed of only 9 joints in each ; feet 18 pairs in number ; caudal 

 lamellae shorter than in preceding species and more spine-shaped. 



Not having seen this species I am unable to describe the structiure 

 of the carapace. 



Hab. Island of Mauritius, M. Desjardins. 



Genus Estheria, Riippell, 

 Carapace smaller in proportion to the size of the animal than in 

 preceding genus, the animal nearly filling the entire cavity ; head 

 large aiid somewhat projecting beyond the margins of the valves ; no 

 pyriform organ ; caudal segment large and terminating in four la- 

 mellae in form of strong curved hooks ; small antennae linear or 

 slightly tapeiing towards the apex ; jaws fleshy ; carapace of a trans- 

 lucent horny or yellowish colour, of moderate thickness, and showing 

 numerous strong concentric ribs ; the surface between the ribs is 

 generally strongly punctate or striated, presenting considerable va- 

 riety in their sculpture, which affords good specific characters ; the 

 animals swim on their belly, and many males are foimd among them. 



A. Valves of carapace dotted or punctate on the surface. 



Sp. 1. Estheria gigas. 



Syn. Daphnia gigas, Hermann, Mem. Apterol. 134. t. 5. f. 4—5 ; 

 t. 9. f. a, 1804. 



Cyzicus Bravaisii, Audouin, Ann. de la Soc. Entomol. vi. Bulletin, 

 p. 9, 1837. 



Isaura Cycladoides, Joly, Ann. des Scien. Nat. 2nd ser. xviii. t. 7, 

 t. 8, t. 9, f. 1-44, 1843. 



Estheria Cycladoides, Lucas, Explor. Scient. de I'Alger. Crus- 

 tace's, 81, 1845. 



Limnadia Hermanni, Koch, Deutsch. Crust. H. xxxv. t. 10. 



Monoculus lenticularis tluinnseus, Faun. Suec. 2051. No. 8; Syst. 

 Nat. ed. 12th, 10.59, No. 8. 



Carapace-valves of a rounded oval form, resembling considerably 

 the shell of a Cyclas ; of a horny amber colour and translucid ; an- 

 terior extremity rather broader than posterior ; both finely rounded ; 

 beaks prominent, situated nearer the anterior extremity of the cara- 

 pace, which is much more convex at that part than elsewhere ; the 

 two valves are marked with concentric strise or ribs, varying from 



