Wright — Limnisthcria : A New Conchostracan Genus. 



203 



implies the assumption that the fonn of ihe animal is in some way an 

 expression of its environment, or rather of the life-history conditioned by its 

 environment , and in order that any such assumption could be made with 

 confidence it would be necessary to demonstrate that such-and-such organ or 

 character was an adaptation to the peculiar conditions. Zoological studies of 

 the modern Conchostraca provide such a demonstration only in the case of 

 certain characters, such as the winged eggs of Limnadia; and it cannot be 

 claimed that even in the very remarkably preserved fossils now described any 

 such specially signiticaut characters have been recognized. 



It is generally considered that confirmation of any such deduction is 

 provided by convergent evidence in the associated fauna. The associated 

 faiina in the present instance, however, embraces only some different genera 

 and species of Conchostraca, and the confirmation derived from such is very 

 limited. One is tempted, nevertheless, to put forward the suggestion that 

 the occurrence of such a fauna m the Carboniferous would be more easily 

 comprehensible under climatic conditions very different from those usually 

 supposed to characterize this period. 



Eefekences. 



G. 0. Saks. — Various papers on Conchostraca in Archiv. f. Mathematics og 

 Naturvidenskab. 



G. 0. Saks. — Fauna Norvegiae, volume i. 



A. C. Packard, Jr. — A Monograph of the Phyllopod Crustacea of North 

 America, with remarks on the order Phyllocarida. U.S. Geol. Surv. 

 Wyoming and Idaho, 1878. Part I. 



T. KuPEKT Jones. — A monograph of the Fossil Estheriae. Pal. Soc, 1862. 



Ph. Bill. — Uber Crustaceen aus dem Voltziensandstein des Elsasses. Mitt. 

 Geol. Lande.sanstalt. Elsass-Lothringen, Band VIII. 1913 and 

 1914. 



Dapav. — Monographic des Phyllopodes Conchostraces. French synopsis. 

 Ann. Sci. Nat. Zool., xx, 1915. p. 39. (Original published in 

 Hungarian.) 



[Explanation of Plates. 



B.l.A. PROC, VOL. XXXV, SECT. B. 



[2 A] 



