KOPOID AND SWEZY: UNARMORED DINOPLAGELLATA 281 



Gyrodinium fusiforme nom. sp. nov. He also described Spirodinium lachri/ma 

 and Spirodinium firave, hoth of which we here transfer to Gfirndinium. LeboTir 

 (1917^) described Spirodininvi (jhiiicioii and a donbtful species as Spirodinium 

 concentricum, wliicli we here transfer to Gyrodinium; also a foi*m as Spiro- 

 dinium. spirale var. acuhnii. which is distinct from Schiitt's species; this we 

 have designated Gyrodi)iium hrifainiia nom. sp. nov. 



In addition to these we have transferred to Gyrodiniuni the following species 



originally allocated elsewhei-e bnt showing undon])ted Gyrodinium characters: 



Gymnodinium ovatiim Gourret (ISS'i) ^ Gyrodi nix m ovatum (Gourret) Kofoid and 



Swezy. 

 Cochlodinium longuin Loliinaiin (IdOS) ^^ Gyrodinium loiiguni (Lohmann) Kofoid and 

 Swezy. 



Kiister (1910) described a form, as Gymnodinium fucorum, which clearly 

 belongs to this genus. His figures and description are inadequate for specific 

 diagnosis, and we therefore place it among the species incertrte sedis. 



Twenty-one species have been previously described in other genera and are 

 here included in Gyrodinium, as follows: 6^. acuUim. (Schiitt), G. contortum 

 (Schiitt), 6^. cornutum (Pouchet), G. crassum (Pouchet), G. fissum (Levander), 

 G. folinceum (Schiitt), G. glnucum (Lebour), G. grave (Meunier), G. hynUnum 

 (Schilling), G. lo^igum (Lohmann), G. lachryma (Meunier), G. ohtusum 

 (Schiitt), G. ovatum (Gourret), G. ovum (Schiitt), G. mitra (Schiitt), G. par- 

 vtdiim (Schiitt), G. pepo (Schiitt), G. pingue (Schiitt), G. pusiUum (Schilling), 

 G. schuetti (Schiitt), G. spirale (Bergh). 



We add to these in this paper the following twenty-three new species : G. 

 l>iconicum> G. eapsulatum, G. caudatum, G. coraUinum, G. culeus, G. dorsum, 

 G. fiaveseens, G. favidum, G. fulvum, G. intorhim, G. herhaceum., G. maculahim, 

 G. melo, G. ochraccum, G. ovoideum, G. postmaculatum,, G. riibricaudatum , G. 

 spumantia, G. suhmarinum, G. truncatum, G. fruneus, G. virgatum, G. viri- 

 descens. 



The following species described under other names are for various reasons 

 fidly outlined in the discussion of the several species included in Gyrodinium 

 under new names as follows : Gyrodinium britannia nom. sp. nov. (= Gymno- 

 dinimn spirale var. aentum, Lebour, 19176), G. cuneafum nom. sp. nov. 

 (^= Gymnodinium gracile, Pouchet, 1885a), G. falcatum nom. sp. nov. 

 {^Gymnodinium fusus, Schiitt, 1895, in part), and G. fusiforme nom. sp. nov. 

 (= Spirodinium, fusus, Meunier) . 



Subgenera of Gyrodinium 

 Two subgenera based upon surface differentiations, as in Gymnodinium, 

 may be separated in Gyrodinium. There are no species in this genus with the 

 thick alveolar ectoplasm found in the species of the subgenus Pacliydinium of 

 Gymnodinium. The basis of separation of the two sul)genera is the presence 

 or absence of longitudinal striations in the ectoplasm. Tlie more primitive sub- 

 genus Laevigella subgen. nov. lacks such markings. Its type species is Gyro- 

 dinium caudatum sp. udw and it includes in addition twenty-four other species. 



