KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 505 



longitudinal flaccllum in this sper-ios pTor-ludes all possibility that the tentacle 

 represents in ErijfJiropsis a modified form of the longitndinal flagelhnn of other 

 Gynmodinioidae. 



Erythropsis pavillardi uom. sp. nov. 



Plate 12, figure 133; text figures SS, 3, 5 



Erythropsis agilis, Pavillard (1905), pp. 48-49, pi. 3, fig. 1. 



E. agilis, Faure-Fremiet (1914c), in part, pp. 27-47, pi. 1, text figs. 1, 3-12. 



Diagnosis. — Small to medinm sized species with ellipsoidal hodx, its length 

 1.3 transdiameters, curved apical horn ; girdle displaced 0.8 transdiameter ; pro- 

 tuberant ocellus, with hemispherical lens; flattened brownish-black pigment 

 mass with red core; elongated, hispid, cylindrical tentacle attaining five times 

 the length of l)od.v. Length, 55-82/'. Mediterranean at Cette, October ; Croisic, 

 west coast of France, September ; Pacific, off La Jolla, California, July. 



Description. — The body is quite regularly ellipsoidal, its length 1.3 to 1.5 transdiameters; 

 dorsGventral diameter slightly less than the transverse. The epicone is a low cone of about 120° 

 with a height of about 0.5 transdiameter, except near the distal end of the girdle, where it slightly 

 exceeds 0.75 transdiameter, or 0.5 the length. Its diameter at the base is about 0.8 transdiameter 

 of the body. Its apex is rounded and bears a short, sinistrally directed, oblique apical horn 

 standing at an angle of 30^-45° from the vertical. It has the appearance of protoplasmic 

 undulations and has been figured by Pavillard (1905) and Faure-Fremiet (1914) as carrying 

 a median flagellum. This is either the displaced transverse flagellum, or is an appearance due 

 to local protoplasmic undulations. Our observations are not conclusive on this point, but favor 

 the latter view. The horn is retracted as cytolysis approaches. The hypocone forms about 0.75 

 of the total body, is somewhat more rotund on the right, and has the contour of a hemisphere in 

 the antapical region. 



The girdle forms a descending left spiral, descending steeply at its distal end to a total 

 displacement in the intercingular region of 0.45 of the total length of the body or at least 0.66 

 transdiameter. In Pavillard 's figure (text fig. SS, 5) there is a considerable displacement of 

 the dorsal side. The girdle almost completely encircles the body. The furrow is broad and 

 shallow, widening slightly beyond the anterior flagellar pore locatd above the ocellus. It is 

 uniform in width thereafter, but constricts to a narrow slit as it enters the sulcus. No attach- 

 ment area was noted at its distal end. The transverse flagellum extends at lea.st half way around 

 the body. No longitudinal flagellum was detected. An anterior paracingular line is clearly 

 defined, with a flattened space equal to the furrow in width between it and the furrow. No 

 posterior paracingular line was noted. 



The sulcus is a narrow groove curved around the right side of the relatively large ocellus, 

 extending as a narrow slit for a short distance below it and then widens out into the deep, 

 axially located, eampamdate, tentacular recess, which extends anteriorly for a distance of 0.35 

 of the total length of the body. Tlie extension of the sulcus anteriorly upon the ei)icone is 

 indicated by the location of what seems to be the transverse flagi'llum thrown forward to the 

 apex from the anterior flagellar pore. Pavillard 's (1905) figure suggests this also. There is, 

 however, a possibility that the margins of tlie sulcus are here contractile. The tentacle is 

 extraoi'dinai-ily large in this sjM'cies. When fully extended it is a fairly uniform c.ylinder 

 attaining five times the length of the bod}^ Pavillard (1905) figui-es it with a uniform diameter 

 of 0.2 transdiameter when fully extended. We find it smaller (0.16-0.18 transdiameter) than 

 this when contracted to one-fourth that length. When extended it is fairly uniform in caliber 



