KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 109 



Tribe 3. GYMNODINIOIDAE Poche emend. 



Gymnodiniaceae Schiitt (1896), p. 1. 

 Gymnodinina Kofoid (1907rt), p. 164. 

 Gymnodiniaceae, Klebs (1912), pp. 438-443. 

 Gymnodinioidae Poche (1913), p. 161. 

 Kyrtodiniaceae Schilling (1913), p. 12. 



Diagnosis. — Dinoflagellata with temporary or permanent longitudinal and 

 transverse flagella, located respectively in sulcus and girdle; flagellar pore or 

 pores ventral ; cell body \Yitliout a tlieca composed of discrete plates, naked or 

 enclosed temporarily or constantly in a continuous, homogenous, gelatinous or 

 cellulose cyst wall usually without a girdle. Fresh water and marine; holo- 

 phytic, saprophytic, holozoic, or parasitic. This group contains 7 families and 

 30 genera. 



Discussiox 



This tribe as described by Poche (1913) contained two families, the 

 Pyrocystidae and the Gymnodiniidae. The family Pyrocysteae was created by 

 Schiitt (1896) for the genus Pijrocijstis Murray, to which he added, as P. lumda, 

 the form he had described the year before as Gijmnodi)iinm lunula. Under 

 the latter name encysted forms of various species of dinoflagellates have been 

 figured as one species. A comparison of the figures of Pouchet (1885«, pi. 2, 

 fig. 3), Schiitt (1895, pi. 25, figs. 80,,, 80s), Blackmann (1902, pi. 4), Wright 

 (1906, pi. 1, figs. 3-6), Dogiel (1906, pi. 1), Okamura (1907, pi. 5, figs. 32a-c), 

 and Apstein (1909, fig. 1) will plainly show that specific and even generic dif- 

 ferences exist between some of the individuals thus figured. Schiitt 's figure 

 80s, plate 25, gives evidences of having a porulate theca. 



We have pointed out elsewhere our views of the limitations of the species 

 Gymnodinium lunula (p. 229). The allocation of the remaining members of 

 the old genus Pi/rorystis with their genetic relationships cannot be determined 

 until their complete life histories have been investigated, since these are prob- 

 ably only phases of the life cycles of other dinoflagellates, both of the thecate 

 and non-thecate types. 



Klebs (1912) has further added to the confusion of this group of organisms. 

 He changed the family Pyrocysteae Schiitt to Phytodiniaceae, excluding from 

 it the species Gymnodinium lunula {Pyrocystis lunula Schiitt), and enlarged 

 it to include four new genera, Phytodinium, Tetradinium, Stylodinium, and 

 Gloeodiniuni. The four new genera thus added may be dinoflagellates, but as 

 they have been figured by Klebs they present none of the diudflagellate charac- 

 teristics and none of the characters of the genus Pyrocystis Murray except the 

 outer wall. They seem more nearly related to the Conjugatae or Chlorophyceae 

 than to the dinoflagellates as that group is at present constituted. Development 



