KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 487 



1. Subgenus Erythropsis (Hertwig) 



Ocellus with single lens and inidivided or non-lobed pigment mass, crowded 

 upon the left margin of the sulcus and protuberant antcrolaterally. Type 

 species E. agilis Hertwig. Includes also E. cochlea (Schlitt), E. corniita 

 (Schiitt), E. pavillardi noni. sp. nov., E. extrudens sp. nov., and E. minor 

 sp. nov. 



2. Subgenus Polyopsidella subgen. nov. 



Ocellus with several lenses superposed, in a linear series, or closely grouped, 

 pigment mass lobed, radiate or scattered. Tyjoe species, E. scarlafinn sp. nov. 

 Includes also E. hispida sp. nov., E. lahnim sp. nov., and E. ricliardi sp. nov. 



Key to the Species of Erythropsis 



1. Ocellus with single subhemispherical lens 2 



1. Ocellus with a compound lens of several distinct elements 3 



2. Tentacle directed posteriorly 4 



2. Tentacle directed obliquely ventral, capitate, with terminal stylet extrudens sp. nov. 



4. Pigment of ocellus bright red agilis Hertwig 



4. Pigment of ocellus black or nearly so 5 



5. Lens subhemispherical, pigment mass spheroidal, nearly twice diameter of lens, hypocone 



subcircular in lateral outline cochlea (Schiitt) 



5. Ijens more nearly hemispherical, less than 1.5 diameter of the lens, hypocone elongated .... 6 



6. Epieone with distinct horn curved towards the left 7 



6. Epieone without horn, hypocone tapering, tentacle tapering, with stylet minor sp. nov. 



7. Tentacle slender, asymmetrically capitate, with stylet cornuta (Schiitt) 



7. Tentacle long and stout, without stylet pavillardi nom. .sp. nov. 



3. Body pervaded anteriorly and ventrally with scarlet pigment, ocellus with a row of five 



lenses scarlatina sp. nov. 



3. Body without scarlet pigment 8 



8. Lens composed of numerous small rounded elements 9 



8. Lens composed of two large, superposed elements richardi sp. nov. 



9. Lens com.posed of a line of five flattened ellipsoids, pigment brownish hispida sp. nov. 



9. Lens composed of a cluster of about seven spheroids, pigment black labrum sp. nov. 



Erythropsis agilis Hertwig 



Text figures SS, 8, 12 



(?) "Acinetea," MetchnikofT (1874), pp. 7-9. 



Erythropsis agilis Hertwig (1884), pp. 204-212, pi. 6, figs. 1-10; (1885), pp. 108-112. 



Spasfostyla sertulariarum, Vogt (18S5a), p. 53; (1885&), pp. 183-187, fig. 1. 



Erythropsis agilis, Metchnikoff (1885), pp. 433^34. 



E. agilis, Delage and Herouard (1896), pp. 387-388, figs. 680, 681. 



E. agilis. Pavillard (1905), pp. 48-49, pi. 3, fig. 1 {=E. pavillardi nom. sp. nov.). 



E. hertwigi, JoUos (1910), p. 203. Lapsus for E. agilis Hertwig. 



E. agilis, Poche (1913), p. 162. 



E. agiUs, Faure-Fremiet (1914c), in part. pp. 27-47, text figs. 2 A-C. PI. 1 and text figs. 



1. 3-12 arc E. pavillardi. 

 E. agilis, Kofoid and Swezy (1917), pp. 89-102, text figs. 9, 10. 



