kofoid: new species of dinoflagellates. 189 



postcingular plates, each with marginal and median rib, sometimes porulate, 

 sometimes with very fine transverse tesselations. 



Length, 100 /x; transdiameter, 38 /x; dorso-ventral, 50 /x. 



Stations, 4730, 4732. 



Oxytoxum curvicaudatum, sp. nov. 



Plate 10, Fig. 61. 



A minute species of robust habit. Body ellipsoidal, transverse and dorso- 

 ventral diameter equal. Length 1.2 times the transdiameter. Altitude of epi- 

 theca scarcely 0.5 of the total length and 0.4 of its transdiameter, in the form 

 of a low dome with blunt apex and convex sides. 



Hypotheca over 2.5 times as high as the epitheca, the diameter of its base 1.25 

 times its altitude. Anteriorly the sides are slightly, if at all, convex. Ant- 

 apex very broadly rounded, terminating in an acute, minute, antapical spur 

 which is deflected ventrally to a horizontal position. 



Girdle about 0.3 of the total length from the apex. Transverse furrow com- 

 pressed, without lists or salient ridges forming a descending right spiral with 

 displacement twice its width, with slight overhang. 



Longitudinal furrow broad and shallow, its length 0.35 of the total length of 

 the body, wider and longer on epitheca than on hypotheca. 



Pre- and postcingular plates marked with eleven longitudinal striae, fainter 

 upon the epitheca. Interstrial areas finely reticulated. 



Girdle ribbed and areolated. 



Length, 41 /x; diameter, 30 /x. 



Station, 4711. 



Oxytoxum gigas, sp. nov. 



Plate 10, Fig. 59. 



A very large species of slender habit, attentuate epitheca and hypotheca, 

 galeate apex, and regularly tapering antapex, greatly displaced girdle, and 

 minute pores in longitudinal striae. 



The body is nearly biconical, the epitheca about 0.4 of the total length. 

 Total length 4 times the dorso-ventral and 4.8 times the transdiameter. 

 Epitheca subcorneal with concave sides, very little flare at the base, slight lat- 

 eral compression, and somewhat elongated slightly galeate apex, broadly 

 rounded and deflected dorsally. Its total altitude 2.2 times its transdiameter 

 at the base. 



Hypotheca a regularly tapering cone, slightly compressed laterally. Its 

 total altitude 3.5 times its transdiameter at the base. Antapex not differen- 

 tiated in form from the postcingular section, forming 0.22 of the total length 

 of the hypotheca. 



Girdle very narrow and very oblique ; furrow deep, with prominent but not 

 salient margins, forming a descending right spiral displaced 7 times its own 

 width, with numerous faint ribs and a few pores. Longitudinal furrow narrow, 



