538 



MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



Slabberia, 406, 407. 

 Spastostyla sertulariaruin, 487. 

 Spirodinium, 279. 



concentricnm, 290. 



cornutum, 293. 



crassum, 294. 



equi, 279. 



fusus, 307. 



grave, 310. 



hyalinum, 311. 



lachryma, 314. 



opimum, 291. 



pusillum, 329. 



spirale, 333. 



var. arutwm, 28.5, 288. 

 var. mitra, 319. 

 var. ohtusum, 319. 

 var. pepo, 326. 

 var. pingue, 327. 



Stein, F., 101. 



Stigma, of fresh-water dinoflagel- 

 lates, 57, 88. 



Sulcus (furrow), structural feature, 

 14; description, 16; function, 

 17. 



Structural evolution, 89'. 

 Surface differentiation, 41. 



Torodinium, 389; description, 389; 



comparisons, 390; historical 

 discussion, 390 ; key to species, 

 390. 

 robustum, 391. 

 teredo, 393. 

 Torsions of the body, 13. 

 Tropho^yte, in Blastodinium cras- 

 sum, 21. 



AVysotzkia, 80. 



