208 TJniversitij of California Publications in Zoology. [Vol.8 



girdle and slightly diiferentiated apical horn. Plate formula 

 3' (or 4'), (or 2)", 6", 6, 6'", 1p, 1"". No longitudinal striae. 



One of the most puzzling cases of confusion which exists 

 among the Peridinidae is that which involves Gonijaulax spini- 

 fera, due, in my opinion, to the defective figure of Claparede and 

 Lachmann (1858-1859) who originally described the species as 

 Pfridinium spiniferum, to Stein's (1883) error in failing to 

 distinguish between the form he described as G. spinifera and 

 that of Claparede and Lachmann, and to the non-acceptance by 

 subsequent writers of Pouchet's (1883) Frotoperidininm digitale 

 as distinct from the species originally described as spiniferum. 

 The acceptance on the part of later workers of the application of 

 the name spinifera to Stein's species has led to the re-description 

 of the minute original form as a new species by Paulsen (1907), 

 Faure-Fremiet (1908), Henckel (1909) and possibly to repeated 

 appearance of Gonijaulax spp. in the plankton records of the 

 International Commission for the Investigation of the Sea. See 

 Ostenfeld (1906, 1909). 



The examination of a wide range of material, and an inspec- 

 tion of all published figures have convinced me that there are 

 two somewhat similar forms but distinct species of Go)iyau1ax 

 widely distributed in the neritic and in the oceanic plankton to 

 some extent. These are, (1) the minute form with widely dis- 

 placed, overhanging girdle and usually two, rarely several, small 

 antapical spines, and (2) a larger form with less displacement 

 and overhang and two larger spines. This first is the original 

 G. spinifera, the type species of the genus, known in later litera- 

 ture as G. leva)ideri (Lemmermann) Paulsen, G. niangini Faure- 

 Fremiet, and possibly G. caspica Henckel. Doubtless it has some- 

 times been confused with and often combined with the other com- 

 mon species, G. digitale (Pouchet) (described as Protopcriditiium 

 digif(de) . 



The other species is the larger and, it seems from all the evi- 

 dence obtainable, is the more abundant one, has less displace- 

 ment and less overhang of the girdle, is often more rugose, and 

 has two prominent antapical spines. It was first described, as 

 above stated, by Pouchet (1883, July- August) and several 



