304 BIOLOGY OF THE PROTOZOA 



4. Attaching peduncle prolonged in rhizoids 



Genus Apodinium 

 Attaching peduncle not prolonged in rhi- 

 zoids Genus Pampodinium 



5. Parasites on copepod eggs 6 



Parasites on diatoms Genus PaidseneUa 



6. Dinospores Gymnodinium-like Genus Chytriodinium 



Dinospores Spirodinium-like Genus Trypanodinium 



7. Intestinal parasites 8 



Coelomic parasites Genus Syndinium 



8. Vegetative forms not attached 9 



Vegetative forms attached Genus Haplozoon 



9. Products of division independent and sepa- 



rate Genus Schlzodinium 



Products of division remain together 



Genus Blastodiniwm 

 Tribe 2. AiviPHiLGTHiODiE 



Four doubtful genera of Dinoflagellida— Amp/w7op/ms Schiitt, Gy77i- 

 naster Schlitt, Achradina Lohmann, Monaster Schiitt. 

 Tribe 3. Peridinioid.e 



1 . Girdle and sulcus present 2 



Girdle and sulcus absent, plant-like 



Family 3. Phytodinid^ 



2. Cuirass usually divided by sagittal suture 



Family 2. Dinophysid^ 

 Shell of distinct plates , no suture . Family 1. Peridinid.® 

 Family 1. Peridinidse. (Deep sea forms omitted). 



1. Cuirass prolonged into horn-like processes 2 

 Cuirass without horns 5 



2. Short horns on hypotheca 3 



Horns on hypotheca and epitheca 4 



3. Horns two or three in number Genus Peridinium 



Horns more than three in number . . Genus Ceratocorys 



4. One anterior, one to three posterior horns 



Genus Ceratium 

 Horns numerous on both halves. . . .Genus Acanthodinium 



5. Body polyhedral Genus Goniodoma 



Body spheroidal Genus Gonyaulax 



Family 2. Dinophysidse. (Deep sea' forms" omitted.) 



1. Form elongate or needle-like Genus Amphisolenia 

 Form ellipsoidal, ovoidal or spheroidal. ... 2 



2. Girdle ridges broad, often funnel-like 



Genus Dinophysis 

 Girdle ridges narrow, never funnel like 



Genus Phalacroyna 

 Family 3. Phytodinidse. 



1. Individuals stalked (usually fresh water) 



Genus Stylodinium 

 Individuals not stalked 2 



2. Chromatophores distributed, protoplasm 



radial Genus Pyrocystis 



Chromatophores peripheral; plasm not 



radial Genus Phytodinium 



Sub-order 2. Adinina. 



With anterior spine-like process Genus Prococentrum 



Anterior end rounded Genus Exuvicella 



