1109 



fiin-ow on (lie free edges of (lie left valve so that the left, valve 

 overlaps the right along the free edges. 



The surface of the carapaces is different, though furrows and 

 lobes are always present. Constant features on the anterior half of 

 the valves are two more or less vertical fnrrows, separated by a 

 narrow lobe. The posterior half may also have a fiu*row. Else the 

 surface is generally smooth and without ornamental markings. 



As may have been inferred from the above statements, the position 

 which I have given to tiiis Ostracod corresponds to the position 

 which in my opinion ^) is due to Beiiriclda tuberculata Klödkn sp., 

 in which there is a furrow on the free edges of the left valve, 

 whereas the right has sharp edges. From Dr. Basslkr of Washing- 

 ton I received a letter the other day, in which he stated that he 

 and Dr. Ulrich considered as posterior what I had assumed as the 

 anterior end in Primitia ToUl Bonnema, Bei/richia tuberculata Klö- 

 DEN sp. and Bei/richia protuberans Boll; but to this I cannot pos- 

 sibly agree. Their opinion is based on the fact that the lower of 

 the two nodes situated at one of the two ends, which in some 

 valves of Beyrickia tuberculata has widened into an "ovarian pouch", 

 would be situated in the anterior half in the position suggested by 

 me, whereas in recent Ostracoda this node is found in the posterior 

 half. In my opinion, however, they disregard the fact that in the 

 position accepted by them, the eyes would be situated at the poste- 

 rior end of the animal, which seems very unlikely. Tliej^ call upon 

 me to prove that the "ovarian pouch" has been at the anterior end 

 in paleozoic Ostracoda. 1 think I have sufficiently proved this with 

 my investigations into the location of the eyes. 



Next I want to state that what Ulrich and Bassler called 

 ^'ovarian pouch" has to be considered as an incubation pouch, and 

 like KiESOW I have no objection to assume that in the paleozoic. 

 Ostracoda this was located in the anterior half of the carapace, 

 whereas in the recent C?/^//t'r6^(//6/>fï M()Ll. it is situated in the posterior 

 half of the carapace but near the centre. 



Finally I tender my best thanks to Mr. Botkk, teacher in the 

 "Middelbare Landbouwschool" (Secondary Agricultural School) of 

 Groningen, who has been kind enough to make the drawings of 

 Kloedendla hieroglyphica Krause sp., necessary for this paper. 



1) These Proc. 16, 1913, p. 67-74. 



