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 bj 

 M. Brono-niart. "^'^-'^^ ^*^ ^^^ ^ ^^^'^^ i»yiu.:jmi:iiio lo hshxiod guiact 

 -f * * ' ^ffn 9/{i n99wi9cf e'>BlTri» 9ffT .^ijraft txjIjjsst isxfjBi 



- Sp. 2. LiMNADiA Mauritiana. tiTem <' has, s' 



L. Mauritiana, Guerin, Mag. de Zool. Class 

 1837; Iconogr. Regn. Anim. Cuv. t. 33. f. 2. M. Edwards," 'fitstl 

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

 Trilobites, Ray edit. t. 6. f. 15. 



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. 

 .jv Not having seen this species I am unable to describe the structure 

 ^ the carapace. ,^ n • ^- n - muu. ., ..^m. 



' Jtiao. Island oi Mauntms, M. Vesjarmns. .tfidT s^jbe sort 



''^ 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 and 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 tapering 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 found among them. 



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



5? Sp. 1. Estheria gigas. tird .ti&i slii 



<' Syn. Baphnia gigasy Hermann, Mem. Apterol. 134»(|j %^>jl&;i/fc^ 

 el. 9. f. a, 1804. ^ " /.,i-\i,;-'.a?;Ti 



3n Cyzicus Bravaisii, Audouin, Ann. de la Soc. Entomol. vi. Bulletin, 

 p. 9, 1837. 



Isaura Cycladoides, Joly, Ann. des S€ien. Nat. 2nd ser. xviii. t. 7, 

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



Estheria CycladoideSy Lucas, Explor. Scient. de 1' Alger. Crus- 

 taces, 81, 1845. 



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



Monoculus lenticularisl Linnaeus, Faun. Suec. 2051. No. 8; Syst, 

 Nat. ed. 12th, 1059, 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 striae or ribs, varying from 



