( 1«7 ) 



X. 



LIMNESTHEriTA : A NEW CONCHOSTEACAN GENUS FEOM THE 

 KITJCENNY C()AL-MEASU1;ES. 



V,\ IVIABEL C. WIMGHT, A.E.C.8c.l. 



[Communicated ky Ti:ofessoi; Gi!KNvii,r,E A. J. Coi.k, vm.s.] 



{PlATES XXIV, XXV.) 



Read Junk 2S. Published AuGi'sr 20, 1920. 

 I. — iNTIiOnUCTIOX. 



The fossils which form the suhject of this paper were found in the 

 Kilkenny Coal-Measnres by one of the officers of the Geological Snrvey of 

 Ireland during their recent revision of tlic Gastleeonier area, and through the 

 courtesy of the Director they were given to the author for description. 



The best thanks of the author are due to Dr. W. T. Caiman, Assistant in 

 the Zoological Department of the British Museum, for his valuable help 

 and guidance in the study of these ancient representatives of a very 

 interesting and highly specialized order of Crustacea ; and to Professor 

 G. H. Carpenter, D.Sc, for many useful hints to a former student. 



The Conchostraca, the order of small bivalved fresh-water Crustacea to 

 wliich these fossils belong, are a group of animals of peculiar interest. 

 Representatives of the order are found in nearly all the great land-masses 

 of the globe, but their distribution is generally restricted to regions of 

 meteorological extremes, where there is a marked contrast between summer 

 heat and winter cold, where prolonged drought i.s f(jllo\ved by sudden 

 rainbursts. 



AH known Conchostraca occur in inland waters, none having been found 

 in the ocean. 



Details of the life-history of the Conchostraca appear to be practically 

 unknown, as far as the literature accessible would show, but the study of 

 Sars on the development of Limnadia' doubtless gives an indication of the 

 mode of life of Conchostraca generally. The little animals appear in small 

 and shallow fresh-water pools, which dry or partially dry in summei'. 



'Fauna Norvegiae, Bd. I. 



E.I.A. PKOC, VOL. XXW, SHOT. li. [Z] 



