kofoid: new species of dinoflagellates. 175 



its transdiameter. The antapicals are slightly unequal, rlivergeiit, conical, acute, 

 their length 0.35-0.45 of the transdiameter. The distance between the anta- 

 pices is 0.38-0.45 of the transdiameter and is 1.3-1.5 times the depth of the 

 postindentation which is subacute with nearly straight sides. 



The antapicals diverge less than in P. fatulipes. 



The girdle is narrow, median, nearly horizontal, furrow ribbed, scarcely 

 impressed, not displaced, with low membranous ribbed lists. Longitudinal 

 furrow with high membranous lists projecting posteriorly beyond the post- 

 margin. 



Plates normal, 3 in median dorsal series. Thecal wall faintly and minutely 

 reticulate with small subequal polygons with very minute centrally located 

 pores. 



Length, 185-245 m; transdiameter, 150-195 /jl. 



Stations, 4732, 4740. 



Peridinium latissimum, sp. nov. 



Plate 5, Figs. 31, 33. 



A small species with foreshortened, dorso-ventrally flattened body and widely 

 separated very short or obsolete antapicals. 



Body pentagonal in face view, anterior margins straight, postero-laterals 

 convex, posterior concave. Its length, 0.8 of the transdiameter and 2.6 times 

 the dorso-ventral. Epitheca, exceeding hypotheca, a low flattened cone, concave 

 ventrally, convex dorsally, its altitude 0.4 of its transdiameter. 



Hypotheca low, its altitude 0.45 of its transdiameter, equalling the distance 

 between the low acute antapicals which in some individuals are almost 

 obsolete. 



Girdle narrow, almost horizontal, slightly postmedian, furrow deeply 

 impressed, scarcely displaced. 



Sutures marked by narrow bands, plates normal, 3 on dorsal side of epitheca. 

 Surface minutely reticulate. 



Length, 112 /x; transdiameter, 89 fi ; dorso-ventral, 35 fx. 



Stations, 4671, 4709. 



Peridinium longispinum, sp. nov. 



Plate 5, Fig. 33. 

 Syn. P. michaelis Ehrbg. in part, Stein ('83), Taf. IX, Figs. 9 and 11. 



A small species of the P. pellucidum group with two intercalary middorsal 

 plates, attenuate apical horn, and two long slender finned antapical spines. 



Body elongated, flattened dorso-ventrally, its total length including spines 

 1.2-1.5 times the transdiameter. Epitheca exceeds the hypotheca, is com- 

 pressed conical with concave lateral faces, and attentuate apical 0.15-0.4 of a 

 transdiameter in length. The altitude is 0.6-0.8 of the transdiameter. 



The hypotheca is low, subtruucate posteriorly, with slightly concave post- 



