170 MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



Description. Attempts to make subdivisions on the type and pattern of processes 

 have been fruitless ; the species is a very variable one. The wall also shows consider- 

 able variation in thickness. 



The processes are from a quarter to a half of the body diameter and are hollow. 

 The process length in an individual is constant, as are the process terminations. The 

 number of processes exceeds 50. Plates can be recognized on damaged specimens 

 and the number of processes ranges from four to seven on each plate. 



Occurrence. London Clay ; Whitechff and Enborne. 



Remarks. C. disjunctum resembles Baltisphaeridium densicomatum (Maier) which 

 however splits equatorially and sometimes has forked processes. B. iaculigerum 

 Klement has longer processes and the archaeopyle is unknown. 



In view of the regular arrangement of the processes, a feature not typical of the 

 genus, the allocation of this species to Cleistosphaeridium must be regarded as provi- 

 sional. 



OTHER SPECIES 



The following species, formerly attributed to Baltisphaeridium, are here provision- 

 ally reattributed to Cleistosphaeridium gen. nov., on the basis of their apparent 

 possession of an apical archaeopyle and in absence of knowledge of their reflected 

 tabulation (if any). Species of especially doubtful character are differentiated with 

 a question mark : 



Cleistosphaeridium ashdodense (Rossignol 1962). Miocene ; Australia. 



} Cleistosphaeridium danicum (W. Wetzel 1952). Paleocene (Danian) ; Baltic. 



Cleistosphaeridium echinoides (Maier 1959). Oligocene ; Germany. 



Cleistosphaeridium ehrenbergi (Deflandre 19476). Upper Jurassic ; France. 



Cleistosphaeridium israelianum (Rossignol 1962). Quaternary ; Israel. 



Cleistosphaeridium leve (Maier 1959). Oligocene-Miocene ; Germany. 



Cleistosphaeridium lumectum (Sarjeant 1960a). Upper Jurassic ; England. 



Cleistosphaeridium machaerophorum (Deflandre & Cookson 1955). Miocene ; 

 Australia. 



Cleistosphaeridium multifurcatum (Deflandre 1937a). Upper Cretaceous ; France. 



? Cleistosphaeridium oligacanthum (W. Wetzel 1952). Paleocene (Danian) ; 

 Baltic. 



Cleistosphaeridium pectiniforme (Gerlach 1961). Oligocene ; Germany. 



Cleistosphaeridium pilosum (Ehrenberg 1954). Upper Jurassic ; Poland. 



Cleistosphaeridium polytrichum (Valensi 1947). Middle Jurassic ; France. 

 ? Cleistosphaeridium spiralisetum (de Wit 1943). Upper Cretaceous ; Netherlands. 



Cleistosphaeridium tiara (Klumpp 1953). Eocene ; Germany. 



Cleistosphaeridium tribuliferum (Sarjeant 19626). Upper Jurassic ; England. 



