52 EARLY TERTIARY OSTRACODA 



ridge is almost straight, short, confined in the mid-ventral region. The surface is 

 densely punctate. 



Dimensions (mm). 



L H w 



Io. 4292 Carapace male 0-43 0-22 o-n 



Io. 4341 Carapace female (holotype) 0-42 0-23 0-16 



Morphotype B 

 (PI. 26, figs. 4-9) 



This is close to Morphotype A but has a more sparsely punctate surface and a 

 second posterior tubercle. In addition, the present morphotype has a well-developed, 

 somewhat elongate anteromedian swelling. 



Dimensions (mm). 



L H W 



Io. 4293 Carapace male 0-44 0-22 0-15 



Io. 4291 Carapace female 0-40 0-22 0-16 



Morphotype C 

 (PL 26, figs. 10-15) 



This has a higher carapace than the other morphotypes. The ventral ridge runs 

 slightly obliquely towards the posterior. It is joined posteriorly to the second 

 posterior tubercle by a short vertical ridge. The anteromedian swelling and the 

 second posterior tubercle form a broken diagonal ridge. 



Dimensions (mm). 



Io. 4289 Carapace male 

 Io. 4290 Carapace female 





L 



H 



w 





o-45 



0-26 



0-17 





0-44 



0-25 



0-18 



Morphotype D 









(PL 27, figs. 1-6) 









The carapace is much more elongate than Morphotype A, B, C and E. The dorsal 

 and ventral margins taper very slightly towards the posterior. An oblique posterior 

 ridge joins the posterodorsal tubercle, the second posterior tubercle and the posterior 

 end of the ventral ridge. The ventral ridge commences above the anteroventral 

 corner, slopes obliquely upwards towards the posterior and meets the oblique 

 posterior ridge in the posterior quarter. A diagonal ridge which may or may not be 

 continuous passes through the second posterior tubercle and the anteromedian 

 swelling. 



Dimensions (mm). 



L 

 Io. 3146 Carapace male 0-51 



Io. 3139 Carapace female 0-51 



H 



W 



0-24 



0-16 



0-24 



0-17 



