KOFOID AND SWEZY: UNARMORED DINOPLAGELLATA 175 



lineopunicum, sp. nov., G. lunula Sehiitt, G. marinmn Saville-Kent, G. minor 

 Lel)Our, G. mirahJe Peuard, G. niusei Danysz, G. ovnlum sp. nov., G. palufstre 

 Scliilling, G. pamdoxtun Scbillmg, G. pseudonocticula Poueliet, G. pundatum 

 Poucliet, G. pijrocijstis Jorgensen, G. ravenescens sp. uov., G. roseolmn 

 (Seluiiarda), G. rotundafum Klebs, G. nibricauda sp. nov., G. scopidosum sp. 

 nov., G. simplex (Lohniann), G. sulcatum sp. nov., G. tintinnicola Lolimann, 

 G. uherrimum (Allmau), G. variaus Maskell, G. viride Penard, G. violesceiis 

 sp. nov., G. vorticella Stein, and G. zacliariasi (Zacharias). 



Subgenus 2. Lineadinium subgen. nov. 



Periplast thin, surface striate with parallel linear striae on epicone and 

 hypocone. Generally of large size. 



Type species is G. heterostriatum nom. sp. nov. It includes also the fol- 

 lowing species: G. acJiromaiicum Lebour, G. attciiuatum sp. nov., G. aureum 

 sp. nov., G. cucumis Sehiitt, G. diploconus Sehiitt, G. hamulus sj). nov., G. hel- 

 veticum Penard, G. lincatii.m sp. nov., G. multilincatum sp. nov., G. midtistri- 

 atum sp. nov., G. rhomhoides Sehiitt, G. ruhrum sp. nov., G. translucens sp. nov., 

 G. vestifici Sehiitt. 



Subgenus 3. Pachydinium suligen. nov. 



Pellicle distinctly thickened, usually conspicuous as a wide zone around the 

 body, \Yith the outer alveolar layer making the surface bossed or mammilate. 

 Surface marked by striae or ridges, or smooth. The t^q^e species is G. pacliy- 

 dermatum sp. uov. It includes besides the t^^i^e: G. ahhreviatum sp. nov., G. 

 amphora sp. nov., G. Infurcatmn sp. nov., G. canus sp. nov., G. coendeum Dogiel, 

 G. costatum sp. nov., G. dogiel i sp. nov., G. gleha Sehiitt, G. gracile Bergh, G. lira 

 sp. nov., G. putiiceum sp. nov., G. radiatum sp. nov., G. sphaericum Calkins, G. 

 situla sp. nov., G. tenuissimum Lauterborn, and G. icilczeki Pouchet. 



Species of Uxcertaix Status in Gymnodinium 



Owing to tlie fact tliat a free, non-thecate phase of brief duration may occur 

 iu the life history of the Peridinioidae, it is possible to mistake tlicui for the 

 true Gymnodinioidea. The characteristics which distinguish such phases are 

 little known. These phases are wont to be more active than the thecate phase 

 of the species and to jje less frequently observed and less completely descril)cd. 

 Tlie activity of the unarmored forms in general tends to introduce into liter- 

 ature records of species based on partial oljservations which do not reveal the 

 relationships or estalilish the status of the form described. 



The following species described in the genus Gi/miiodijiiunt are in our 

 opinion so imperfectly characterized as to render their allocation tentative and 

 to require fuller descriplion Itcl'di'c their status therein aud their relationships 



