282 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



The more higlily differentiated subgenus with striate pellicle has for its type 

 species Gi/rodiuiuni spiralc (Bergh), the type of Gijrodiuiu))) sensii Jatu. In 

 addition to this it includes tweuty-two other species. This subgenus contains 

 the most of the species with maxunum displacement of its gii'dle and torsion of 

 the body, highest coloring, and development of pigment. 



In addition there are imperfectly kuo^^^l species which must for the present 

 be left unassigned in species incertae sedis to wit: G. fncoriim (Kuster) and 

 G. concentricum (Lebour). 



Subgenus 1. Gyrodinium (soisu strict h) subgen. nov., fig. DD 



Gyrodinium with surface striate with parallel longitudinal striae. Type 

 species is G. spirale (Bergh). This subgenus contains besides the tj'pe the 

 following species : G. hritannia nom. sp. nov., G. coralluuon sp. nov., G. crassum 

 (Pouchet), G. cuncatum nom. sp. nov., G. fission (Levander), G. fidvum. sp. 

 nov., G. glaucum (Lebour), G. grave (Meunier), G. herhaceum sp. nov., G. 

 Ion gum (Lohmanu), G. macidatum , G. ohtustcm nom. sp. nov., G. ochraceum 

 sp. nov., G. pepo (Schiitt), G. pingiie (Schiitt), G. postmaculatum sp. nov., 

 G. ruhri con datum sp. nov., G. scJitietti (Schiitt), G. sulnnan'nuw sp. unv., G. 

 triDicus sp. nov., G. virgatum sp. nov., G. viridcscens sp. nov. 



Subgenus 2. Laevigella subgen. nov., fig. CC 



Gyrodinium wdth surface free from longitudinal parallel markings, with or 

 without chromatophores. The type species is G. caudatum sp. nov. This sub- 

 genus includes besides the type the following species: G. aciitum (Schiitt), 

 G. hiconiciim sp. nov., G. cajysidatKm sp. nov., G. contort um (Schiitt), G. cor- 

 nidum (Pouchet), G. cidcus sp. nov., G. dorsum sp. nov., G. faJcatum nom. sp. 

 nov., G. flavescens sp. nov., G. favidum sp. nov., G. foliaceum nom. sp. nov., 

 G. fusiforme nom. sp. nov., G. intortum sp. nov., G. hycdinum (Schilling), G. 

 lachryma (Meunier), G. melo sp. nov., G. mitra nom. sp. nov., G. ovoideum 

 sp. nov., G. ovatum (Gourrett), G. ovum (Schiitt), G. parvulum (Schiitt), G. 

 pHsiUum (Schilling), G. spumantia sp. nov., and G. truncatum sp. nov. 



Key to the Species of Gyrodinium 



1. Surface free from striae or other markings, with or without chromatophores 



(subgemis Gyrodinium^ 7 



1. Surface striate, chromatophores absent (subgenus Laevigella) 2 



2. Chromatophores present - 3 



2. Chromatophores absent - 6 



3. Chromatophores j'ellow - 4 



3. Chromatophores green 5 



•i. Chromatophores small, rod-shaped, yellow ochre falcatum nom. sp. nov. 



4. Chromatophores disklike, yellow pusillum (Schilling) 



