;i8S U'liivcrsitii of California I'libliralions in ZoohifjU- [Vol.4 



and /' Xila. to a syjidiiym of C. fiisus, in the explanation of his 

 Tafel 16, while P cufiramhuim is referred to ('■ farca, m the 

 explanation of his Tafel ]5. 



It is not improbable that the i-cduction of these species of 

 Ehrenbor^i's to synonyms by Stein ('S:^) is due to Sti'in's knowl- 

 edii'e only of an earlier paper of Ehi'enberj;"s ("•iO) in whieh he 

 briefly diagnosed these speeies, but wilhout figures, in the absence 

 of which their reeo.miition is difficult, if not impossible. Later 

 authors have, with the exception of Saville-K<'nt ('Hl-'82;, con- 

 curred in Stein's opinion. 



I have elsewhere ( :07) noted the correctness of Ehrenberg's 

 recognition of C. cugratnmum. I wish here to revive two of his 

 other species of Ci latiutn. which ai"e equally valid, and to note 

 the instances in which several of them have cre|>t into literature 

 under new names in recent years. 



Ceratium trichoceros (Ehrbg.). 



Ehrenberg ('60), p. 791, as Peridinium Trichoceros. 



Ehrenberg ('74), p. 3, Taf. (1), fig. 1, as Peridinium Trichoceros. 



Saville-Kent ('SO- 'SI), vol. 1, p. 457, as Cerntium xeta. 



Stein ('83), explanation of Taf. 16, as a synonym of C. tripos. 



Karsten (:ii6), Taf. 22, fig. 31b, as C. flagelliferum C'leve; fig. 

 32a and b, as C. fiageUiferum forma crassa n. rar. The latter 

 figure is questionably referred to C. trichoceros by me. 



Kofoid (:0S), p. 362, figs. 15-19. 



This speeies of Ehrenberg's is well defined by its rigid habit 

 of growth, the wide-spreading major flexures of the antapicals. 

 and the slender horns with pointed closed tips. Its three horns 

 are subparallel and the antapicals are usually noticeably serrate 

 along their posterior margin toward their major flexures. 



It has probably been confused in the past with C flagelli- 

 ferum Cleve (:00), a form of C. inflexion Gourret ('83), which 

 has more flexible or variously incurved or recurved antapicals 

 and exhibits in general a more lax habit of growth than C tri- 

 cJwceros. The tips of the antapicals of C. inflc.cum are con- 

 tracted, usually have a small terminal pore and are sometimes 

 swollen, differing in these particulars from the pointed closed 

 tips of C. trichoceros. C. inflexion also lacks, as a rule, the 

 prominent posterior serrations of C. trichoceros. 



