MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 139 



Type species. Hystrichosphaeropsis ovum Deflandre 1935. Upper Cretaceous ; 

 France. 



Remarks. The name Hystrichosphaeropsis was originally proposed as a separate 

 genus, but was later relegated to the status of a subgenus of Hystrichosphaera 

 (Deflandre 19366). Its status as a separate genus was implicitly revived by the 

 inclusion of this name in a list of valid genera by Eisenack (1963a : 118). 



The generic name Rottnestia was subsequently proposed by Cookson & Eisenack 

 (1961b : 40-42). Deflandre, in a letter to the author (written in 1963 and here 

 quoted by permission) comments as follows : 



" Le genre Rottnestia Cookson et Eisenack 1961 est synonyme du genre Hystri- 

 chosphaeropsis Defl. 1935 (subgen. in Defl. 1937). Le type (H. borussica Eisenack) 

 est tout a fait sembable a H. ovum Defl. 1935. Les autres especes d' Hystricho- 

 sphaeropsis sont H. simplicia (C. et E.) et H. wetzeli ; Defl. 1935. " 



On this basis, it appears necessary that the generic name Rottnestia should be 

 abandoned. The revised diagnosis of Hystrichosphaeropsis, here formulated, 

 incorporates in general the diagnostic features quoted in both earlier diagnoses (i.e. of 

 Hystrichosphaeropsis and Rottnestia) ; but forms lacking nodal processes are excluded 

 and attributed to the new genus Psaligonyaulax. The author was courteously 

 permitted by Prof. Deflandre to examine the type species during a visit to Paris in 

 1961 ; the tabulation was elucidated to be as here quoted. The figures of Rottnestia 

 suggest the same tabulation. 



other species 



Although Prof. Deflandre considers Rottnestia borussica to be probably conspecific 

 with Hystrichosphaeropsis ovum, this remains to be confirmed : the former species is 

 thus provisionally retained as Hystrichosphaeropsis borussica (Tertiary ; Rottnest 

 Island, Australia). 



Hystrichophaeropsis wetzeli Deflandre 1935 (Upper Cretaceous ; France) accords 

 with the revised diagnosis. 



Genus CARPODINIUM Cookson & Eisenack 19626 : 489 



Type species. C. granulatum Cookson & Eisenack 1962b. Lower Cretaceous 

 (Aptian-Albian) ; Australia. 



Remarks. This genus was diagnosed in the following terms (19626 : 489) : 



" Shell elongate — oval to ellipsoidal, divided almost equally by an equatorial 

 girdle. Epitheca with a distinct horn, hypotheca devoid of horns or projections. 

 Pre- and post-equatorial plates probably six in number, elongate trapezoidal 

 and bordered with wings. The longitudinal furrow broadens gradually from 

 the apex to the antapex. A pylome develops on the dorsal surface of the epi- 

 theca. " 



