BY G. I. PLAYFAIR. 



809 



acterised by the two apical dorsal plates in the epivalve being 

 very small. These show up very clearly in the dorsal view of 

 the cell, forming the upper corners of the 4th equatorial plate. 

 T lie type is very angular, being strongly faceted with concave 

 plates. Epivalva with a strongly accentuated apical pit, the rim 

 drawn out and appearing as a pair of minute spines. Hypo- 

 valve with longitudinal furrow greatly dilated and carried right 

 back to the hinder edge. The antapical plates are very unequal 

 in size and of very peculiar shape, being greatly hollowed out on 

 the ventral side by the dilated longitudinal furrow. Specimens 

 are occasionally found with the plates equal however. 



Var. conicum, n. var. (Text-fig. 16 /). 



Forma minus angulata; tabulis minime concavis. Epivalva 



Text-fig. 16. 

 Peridinium intermedium niihi. (a) dorsal view, (b) ventral view, 

 (c) epivalve, (d) hypovalve, (e) rarer form of hypovalve, (/) var. 

 conicum, n. var. (x 660). 



late-conica, subtriangularis ; lateribus fere rectis; fovea apicali 

 sine spinis. Hypovalva depressa, subtruncata, spinis ternis 

 armata . 



Long. 38, lat. 38, epiv. alt. 23 ^. Sydney Water Supply 

 (100). 



