136 ON PERMIAN ENTOMOSTRACA FROM 



Roessleri. with its uniformly sculptured surface, punctured ven- 

 tral ridge, and weli-marked oval spot, may be regarded as a 

 separate variety (K. Permiana, var. Richteriana). 



I quite agree with Mr. Kirkby in his observations on the 

 A'. [Cithers) sticta, of Keyserling (see above, p. 132), which 

 closely resembles the specimens referred to by Richter to K. 

 (Cythere) Roessleri, of Reuss. Nor can I see, in Keyserling's 

 figures, any s;?ec?^c differences between his C. Schreuku, C. sticta, 

 and C. grapta; they are, probably, varieties of K. Permiana; and, 

 until we can compare the specimens, we may recognise them as 

 K. Permiana, var. Schrenkii, sticta, and grapta. 



The other species of Kirkhya, with which I am acquainted, has 

 a thick oblong carapace, with its ends nearly uniform in thick- 

 ness with the central portion. Its ventral border is thick and 

 doubly ridged. The surface of the valves is reticulated, and 

 characterised by two somewhat semicircular ridges, one within 

 the other, their ends touching the dorsal edge. The oval spot is 

 nearly central, and placed at the curve of the inner and smaller 

 ridge. The specimens are in the Hunterian Museum of the 

 Royal College of Surgeons, of London, and were collected and 

 presented to John Hunter by the Rev. Dr. Ure. They are from 

 the lower Carboniferous shales, near Glasgow. I propose to de- 

 nominate this species Kirkhya Urei. 



The generic characters of Kirkhya may be stated as follows: — 



Animal enclosed in a bivalved carapace ; carapace equivalved ; 

 carapace-valves thick, oblong; anterior and posterior extremities 

 more or less rounded ; ends of the dorsal border somewhat acute ; 

 ventral border straight in the centre and curved at the ends. 

 Valves usually wider at the caudal than at the cephalic extre- 

 mity, convex, ridged strongly on the ventral border and at the 

 ends ; the ventral edge of one valve (dextral) slightly overlap- 

 ping that of the other ; surface impressed with a small subcentral 

 oval hollow, and more or less ornamented with a reticulate 

 sculpture and ridges. Hinge probably consisting of a simple 

 adaptation of the dorsal edges and their union by membrane. 



In the general form, hingement, and mode of overlap, Kirkhya 

 resembles Beyrichia ; and K. Urei slightly approaches some 



