kofoid: new species of dinoflagellates. 185 



Heterodinium superbum, sp. nov. 



Plate 8, Fig. 49. 



A very small species of robust habit, spheroidal body, and short spine-like 

 antapicals. Reticulations rather coarse. 



The body is elongated spheroidal, its length 1.28 times the transdiameter 

 and 1.35 times the dorso- ventral diameter. The body is very rotund at the 

 girdle. The epitheca and hypotheca are equal in length, but the latter is more 

 rotund. The epitheca is subcorneal, its altitude is 0.56 of its transdiameter. 

 It flares slightly at the girdle and its lateral margins have but little convexity. 

 There is a partially developed apical horn, deflected to the right and set some- 

 what to the ventral side of the axis. 



The hypotheca is very rotund, low dome-shaped, its altitude between the 

 horns being a little less than 0.5 of its transdiameter. The antapicals are set to 

 the ventral side in line with the apical, causing an abrupt shelf where the 

 dorsal antapical plate joins the postcingulars. The right is 1.15 times the 

 length of the left, which is 0.2 of a transdiameter in length. They are 

 tapering, spine-like, with 0.3 of a transdiameter between tips. The postinden- 

 tation is very shallow and the postmargin a broad curve. 



The girdle is not oblique, is displaced its own width. The anterior list is 

 very heavy, the posterior light and obsolete distally. The furrow is scarcely 

 impressed and is heavily ribbed. 



The plates are normal, the left intercalary triangular in form. The thecal 

 wall is coarsely reticulate and porulate. There are about 30 reticulations in 

 the dorsal apical and 15 contiguous to the girdle on the dorsal side. Suture 

 lines with narrow ridges, minor reticulations or serrations. 



Length, 74 p ; transdiameter, 59 /x. 



Station, 4699. 



CENTRODINIUM, gen. nov. 

 Steiniella (?) Cleve. 



Ceratiinae with laterally compressed midbody contracted to an apical horn 

 with pore and a single median antapical, median girdle on midbody, trans- 

 verse furrow impressed, forming a descending right spiral. Longitudinal 

 furrow mainly confined to hypotheca. Theca fully divided in discrete plates. 

 Suture lines faint. Epitheca composed of apical and precingular series, 2 

 plates (possibly 4) in the former, and 6 in the latter. Girdle not distinctly 

 divided into constituent plates. Hypotheca composed of 5 precingulars, 4 

 antapicals, and one dorsal intercalary. Thecal wall hyaline, structureless, 

 porulate. Small ventral pore above the flagellar pore. Chromatophores 

 present. 



In warm temperate and tropical seas. 



