DINOFLAGELLATA 231 



C. hirundineUa (Muller) (Figs. 80; 104, e). 1 apical and 2-3 

 antapical horns; seasonal and geographical variations; chain-for- 

 mation frequent; 95-700yu long; fresh and salt water. Numerous 

 varieties. 



C. longpipes (Bailey) (Fig. 104,/). About 210^ by 51-57^; salt 

 water. 



C. tripos (Miiller) (Fig. 104, g). About 225)U by 75/x; salt water. 

 Wailes (1928) observed var. atlantica in British Columbia; Mar- 

 tin (1929) in Barnegat Inlet, New Jersey. 



C. fusus (Ehrenberg) (Fig. 104, h). 300-600^ by 15-30^; salt 

 water; widely distributed; British Columbia (Wailes), New Jer- 

 sey (Martin), etc. 



Genus Heterodinium Kofoid. Flattened or spheroidal; 2 large 

 antapical horns; annulus submedian; with post-cingular ridge; 

 sulcus short, narrow; shell hyahne, reticulate, porulate; salt wa- 

 ter. Numerous species. 



H. scippsi K. (Fig. 104, i). 130-155/x long; Pacific and Atlantic 

 (tropical). 



Genus Dolichodinium Kofoid et Adamson. Subcorneal, elon- 

 gate; wdthout apical or antapical horns; sulcus not indenting epi- 

 theca; plate porulate; salt water. 



D. lineatum (Kofoid et Michener) (Fig. 105, a). 58/x long; east- 

 ern tropical Pacific. 



Genus Goniodoma Stein. Polyhedral with a deep annulus; epi- 

 theca and hypotheca slightly unequal in size, composed of regu- 

 larly arranged armored plates; chromatophores small brown 

 platelets ; fresh or salt water. 



G. acuminata (Ehrenberg) (Fig. 105, h). About 50^ long; S'alt 

 water. 



Genus Gonyaulax Diesing. Spherical, polyhedral, fusiform, or 

 elongated with stout apical and antapical prolongations, or dorso- 

 ventrally flattened; apex never sharply attenuated; annulus equa- 

 torial; sulcus from apex to antapex, broadened posteriorly; plates 

 1-6 apical, 0-3 anterior intercalaries, 6 precingulars, 6 annular 

 plates, 6 postincingulars, 1 posterior intercalary and 1 antapical; 

 porulate; chromatophores yellow to dark brown, often dense; 

 without stigma; fresh, brackish or salt water. Numerous species. 



G. polyedra Stein (Fig. 105, c). Angular, polyhedral; ridges 

 along sutures, annulus displaced 1-2 annulus widths, regularly 

 pitted; salt water. "Very abundant in the San Diego region in the 



