[8 APPENDIX TO "STUDIES ON MESOZOIC 



VI. TAXONOMIC REVISIONS MADE BY OTHER AUTHORS 



Taxonomic revisions made by other authors in the period since publication of our 

 ' Studies on Mesozoic and Cainozoic dinoflagellate cysts ' have caused the omission, 

 from the preceding sections, of a number of species transferred to new genera in the 

 earlier work without new combinations for them being validly published. It is felt 

 that these should be briefly listed here, in order to provide comprehensive coverage. 



(a) The species Hystrichosphaeridium zoharyi Rossignol, 1962, whose transfer to 

 the genus Polysphaeridium was tentatively proposed by Davey & Williams 

 (1966b ; 95), has been made type for a new genus, Hemicystodinium, by Wall, 

 (1967 ; no) on the basis of its development of an epitractal archaeopyle. 



(b) The species Hystrichosphaeridium israelianum Rossignol, 1962 (placed in the 

 genus Baltisphaeridium by Downie and Sarjeant, 1964) and Hystrichosphaeri- 

 dium centrocarpum Deflandre and Cookson, 1955 (placed in the genus Balti- 

 sphaeridium by Gerlach, 1961), were transferred to the genus Cleistosphaeri- 

 dium by Davey, Downie, Sarjeant & Williams (1966 ; 170). Both have been 

 placed in a new genus, Operculodinium, by Wall (1967 ; no-n), H. centro- 

 carpum being chosen as type. This genus resembles Exochosphaeridium 

 Davey, Downie, Sarjeant & Williams (1966 ; 165) in its development of a 

 single-plate precingular archaeopyle, differing in the apparent absence of an 

 enlarged apical process, and in the presence of striations on the bases of the 

 processes. 



(c) The species Hystrichosphaeridium machaerophorum Deflandre & Cookson, 1955 

 (placed in the genus Baltisphaeridium by Downie & Sarjeant, 1963), was 

 transferred to the genus Cleistosphaeridium by Davey, Downie, Sarjeant & 

 Williams (1966 ; 165). It has been made the type of a new genus, Lingulo- 

 dinium, by Wall (1967 ; 109-10), on the basis of its possession of a precingular 

 archaeopyle formed by loss of the equivalents of four or five plate areas. 



(d) In three instances, the proposed type species of new genera formulated in our 

 earlier work were not initially validly transferred to those genera (I. C.B.N. 

 Art. 33) and were subsequently validly transferred by Loeblich & Loeblich, 

 (1968). These are : Dichadogonyaulax culmula (Norris, 1965) Leoblich & Loe- 

 blich, 1968 ; 211 [= Dichadogonyaulax culmula (Norris, 1965) Sarjeant, 1966b ; 

 153, nom. nud.] ; Duosphaeridium nudum (Cookson, 1965) Loeblich & Loe- 

 blich, 1968 ; 211 [= Duosphaeridium nudum (Cookson, 1965) Davey & Williams, 

 1966b ; 97, nom. nud.] ; and Rhaetogonyaulax rhaetica (Sarjeant, 1963) 

 Loeblich & Loeblich, 1968 ; 212 [= Rhaetogonyaulax rhaetica (Sarjeant, 1963), 

 1966 ; 97, nom. nud.]. 



(e) As a result of a redefinition of the genus Cribroperidinium Neale & Sarjeant 

 (1962), proposed by Davey (1968a ; 125), the species Gonyaulax edwardsi 

 Cookson & Eisenack 1958, Gonyaulax muderongensis Cookson & Eisenack 

 1958, and Gonyaulax orthoceras Eisenack 1958 sensu stricto (i.e. excluding 

 G. parorthoceras Davey 1968b), whose reallocation to Gonyaulacysta was 

 proposed by Sarjeant (1966 ; 130 ; 131 ; 121-3), are now transferred to 

 Cribroperidinium (Davey 1968a ; 128). 



