i6o MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 



further complicated matters by designating other forms " H. cf. striolatum " (pp. 

 399-400, text-figs. 13, 14) : both forms show " archaeopyles ", but neither appears 

 truly comparable to Ueflandre's species. 



In a second paper describing Danian assemblages, Wetzel (1955 : 38, text-fig. 11) 

 reiterated his proposals and described a new form, under the name H. hirtum subsp. 

 amplum. The text-figure shows a spherical form with short, stiff spines, again more 

 approaching Ehrenberg's text-figure than the specimen as redescribed. 



The name striolatum has been employed in equal measure — by Valensi (1955 : 593, 

 pis. 4, fig. 10 ; pi. 5, fig. 3) in describing French Cretaceous forms from Magdalenian 

 worked flints ; by Gocht (1959 : 73, pi. 7, fig. 10) who described forms from the 

 German Lower Cretaceous as H. cf. striolatum ; and by Gorka (1963 : 68-70, pi. 10, 

 fig. 6-7, text-pl. 8, figs. 5-6) who used the same name to designate forms from the 

 Upper Cretaceous of Poland. 



Downie & Sarjeant (1963, pp. 91-2) compromized by including both names 

 (hirsutum and striolatum) in their list of species attributable to Baltisphaeridium. 

 Similarly, both names figure in their list of valid taxa (Downie & Sarjeant 1964: 91, 

 97). In the latter work, hirtum is listed as an invalid alteration of hirsutum (p. 166). 



The present situation thus remains confused. One of the authors (R.J.D.) was 

 permitted, through the courtesy of Prof. Deflandre, to make a full re-examination of 

 the holotype of striolatum which confirmed that Ehrenberg's and Deflandre's species 

 are conspecific. For the reasons enunciated by Deflandre (1946), the species must be 

 designated striolatum. The name hirtum, whether or not originally written in error, 

 was merely pencilled on to a slide by Ehrenberg and was not validly published until 

 1952. It is therefore either an invalid alteration of the name hirsutum or a junior 

 synonym of striolatum ; however regarded, it cannot be retained. 



The holotype of the species striolatum (in the laboratoire de Micropleontologie, 

 Ecole Pratique des Hautes Etudes, Paris, preparation AH 89, flint S.52) is contained 

 in a flint flake. It is here provisionally included in the new genus Exochosphaeridhtm, 

 on the basis of similarity in general structure to the type species, E. phragmites. 

 However, the apical process characteristic of the genus was not certainly observed, 

 nor was an archaeopyle noted. 



In view of the highly doubtful character of the morphology of the three subspecies 

 amplum W. Wetzel, minor O. Wetzel and varians O. Wetzel, it is considered that 

 their erection to specific status would be inappropriate until a full restudy of the 

 holotypes has been undertaken. They are therefore provisionally regarded as 

 subspecies of E. striolatum. 



Genus SURCULOSPHAERIDIUM nov. 



Derivation of name. Latin, surculus, branch or twig ; sphaera, a ball — with 

 reference to the branched nature of the processes radiating from the central body. 



