994 
der rechten Klappe” and ‘Langs des Bauch-, Vorder- und Hinter- 
randes greift die rechte Klappe über...” 
The identity of the two genera, however, appears much more 
clearly from the figures Géricn gives of his Poloniella devonica and 
BoNNeMa of Aloedenella hreroglyphica and which are partly copied 
on the accompanying plate. If we compare Fig. 1 of Poloniella 
devonica with Fig. 2 of Kloedenella hieroglyphica and Fig. 7 of the 
former with Fig. 8 of the latter, it appears that also of the former 
the right valve has undoubtedly a notch in which a process of the 
left valve fits. The fact that Güricu represents complete carapaces 
of Poloniella devonica and loose valves of the other Ostracoda, 
originating from the same locality, renders it also probable that in 
Poloniella the connection of valves is present, which is characteristic 
of the genus Kloedenella. 
At the same time it is easy to see that the furrows on the lateral 
sides of the carapaces of the Ostracoda correspond, when we only 
assume that in Poloniella devonica the anterior and the posterior 
furrows are joined at the ventral side, so that we cannot distinguish 
here the two small furrows that are present in Kloedenella hieroglyphica. 
If we compare the figures 7 and 9 of Poloniella devonica which 
were given by GUricu, it strikes us immediately that the carapaces 
illustrated are very different in thickness. This is easily explained 
by assuming that the first comes of a male and the second of a 
female individual, as has occurred in many other Ostracoda. (1, p. 79; 
7, p. 66). The carapace of the female is taken to be thicker than 
that of the male as a result of the stronger development of the 
genital apparatus. 
The same phenomenon appears also in Kloedenella hieroglyphica. 
Among the material of this Ostracod, which is to be found in the 
Mineralogical-geological Institute at Groningen, occur two kinds of 
carapaces viz. thick ones which I think originating from females 
(Fig. 10) and less thick ones originating from males (Fig. 8). 
Thus we can see that in both genera Poloniella and Kloedenella 
sexual dimorphism appears in the same manner. 
I, therefore, do not doubt the identity of the genera Poloniella 
and Kloedenella. The former being founded Beene latter, the genus 
Kloedenella must be abandoned. 
The criteria of the genus Poloniella are: carapace elongate and 
small; the length usually less than 15 mm.; the thickness of the 
carapace of the male individuals practically everywhere the same; 
in the female much larger especially at the posterior end. At the 
anterior and posterior ends the carapace is equal in height with the 
