I foiiiifl some years ago in Primitla ToJli üonnkma (22, p. 16) fi-oiii 

 the Kiickeis formation and besides of what I noticed in valves of 

 Beijrichia tuherculata Klöden sp. 



In Primitla Tola (fig. 1) I found in the first place that the shells 



Fig. 1. 

 Left valve of rrimilia 

 BONNEMA. X 15. 



Tolli 



Fig. 2. 

 Transverse section of the entire 

 carapace of Primitia Tolli Bonnema, 

 through the part of the lateral eyes, 

 anterior view. X 13. 



are very thin on the spots where the valves have a more or less 

 distinct node (fig. 2). As according to Zenker (24, p. 8) this is also 

 the case with Ostracoda living in the sea, on the spots where the 

 two composite eyes are located, the short edge of the two valves 

 which is nearest to the node, appears to be the anterior edge. As 

 the straight edge is to be regarded as hinge line, accordingly as dorsal 

 edge, the orientation of the shell of this Ostracod is settled. 



Besides I found that the two valves have a furrow behind the 

 node. In this furrow there is a round spot in the lower part indi- 

 cating the place where on the interior of the valve the adductor 

 is listened. 



Further it appeared that the free edges of the right valve are 

 sharp and that on those of the left valve there is a deep furrow. 

 When the valves are closed the sharp edges of the right valve lie 

 in the deep furrow of the left one. 



In order now to determine which of the two short edges of the 

 valves of Beyrichia tuherculata is to be regarded as anterior, I 

 investigated in the first place whether there was any sign of a 

 muscle impression. 1 succeeded in discovering this in valves origi- 

 nating from an erratic boulder of Beyrichian limestone found at 

 Vollenhove. Now the muscle impression is located in the furrow 

 betw^een the oval node and the three bulb-like parts, as a ligiit oval 

 spot, the edge of which passes upward into a curved line, which 

 runs to the superior part of the oval node (fig. 3). 



From the location of the muscle impression I think I am justified 

 ill concluding that the oval node may be identified with the node 



