190 



Procp.eilinfj!< at' the Royal Irish Academy. 



This failure to get anything but the outline of the shell in those cases 

 where the limbs are preserved is characteristic also of the Kilkenny material. 



The best of the Kilkenny fossils show the two valves of the carapace 

 'either lying on top of one another (fig. 5 a) or .spread apart in the same 

 plane (fig. 1 a). These, however, show only their outline and delicately 

 ciliated mar^ns. The ornamentation of the shell surface has, with the very 

 doubtful exception of a single penultimate ring in specimen 5 (=fig. 2 a), 

 either completely disappeared or was never present. 



Fir. j — T<ro itpfcimens with the valvn of the carapace spread apart : — 



A. SpM-imen 5, ihoving antennae anJ telsnn viih an indication of the outline of the 



body. For <ieuils of telaon, ace fig .1, IM. XXV. 



B. Specimen C, ahoviog antennae and one mandible The nature of the small V-shaped 



markinfi adjoining the mandible it unknoirn, but thoT possibly represent portions 

 of the triangular bale. (Cf. PI. XXIV, 6g. I.) 



No known living Conchostracan, with the single exception of the aberrant 

 genus Limnetis, is without the concentric ridges which mark the moulting 

 perio*!.", and they are present also in the fa<wil carapaces of Estherian type 

 that have hitherto l>een described. Lying generally in their proper relation 

 to these outlined valves, but often much distorted, are various lx)dy- 

 memlxTS — antenna/>, claspcrs, mandibles and tclson — in a Ijeautifiil state of 

 preservation, and all of normal Rstlii-rian type. The Itody-segments are 

 less api>arent, but can V detected in s<^>mc instances. 



Fio. 3.— Shell fSpetimen 1 

 which ne^' 



tted vith murh-crushod appendage material, to 

 /trapace ralves were attached. 



The non-appearance of the shell omamonUition is the more remarkable 



