186 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



Centrodinium complanatum (Cleve). 



Steiniella (?) complanata, Cleve. 



Length 4-5 times dorso-ventral diameter. Midbody not abruptly set off 

 from apical or antapical. Antapex not deflected to the left, bearing three 

 short spinules. Apex and antapex coarsely porulate, the former not abruptly 

 truncate. 



Length, 300-400 /* ; dorso-ventral diameter, 75-80 p. 



Station, 4719. 



Centrodinium deflexum, sp. nov. 



Plate 9, Figs. 53, 54. 



A medium-sized species with narrow apical, and antapical abruptly deflected 

 to the left at an angle of 45°. 



Body not greatly elongated, length 1.3 times the dorso-ventral diameter and 

 7 times the transdiameter. Epitheca and hypotheca nearly equal. Midbody 

 laterally compressed, not flaring at the girdle laterally, dorsal and ventral 

 margins both convex, epitheca abruptly contracted to the slender apical horn 

 whose length is 0.5-0.12 of the transdiameter in length and broadly rounded 

 at the end. This horn is directed obliquely dorsally in line with the trend of 

 the ventral margin. 



The hypotheca resembles the epitheca in proportions in lateral view, but 

 the antapical horn is directed ventrally subparallel to the direction of the 

 apical. In side view this is seen to be bent abruptly to the left as it leaves 

 the midbody, at an angle of about 45°. The antapex bears 3 short spinules, 

 1 on the left and 2 on the right side. 



Thecal wall hyaline, porulate, structureless, sutures faintly marked, apical 

 and antapical regions coarsely porulate. 



Length, 145-200 \i ; dorso-ventral diameter, 66-75 /x. 



Stations, 4730, 4732. 



Centrodinium elongatum, sp. nor. 



Plate 9, Fig. 53. 



A large species with truncate apex, epitheca shorter than hypotheca and 

 long antapical horn. 



Body elongated, length 3-4 times the dorso-ventral diameter and 7 times 

 the transverse. Epitheca 0.3 of the total length, laterally compressed, flaring 

 abruptly laterally to the girdle, ventral margin nearly straight, dorsal convex. 

 Apical horn stout, short, abruptly truncate, its length equal to or exceeding 

 its dorso-ventral width, and 0.35 of the dorso-ventral diameter in width. 



Hypotheca greatly elongated, tapering within a transdiameter of the apex 

 into the stout elongated antapical horn, its length 1.7-3 times its dorso-ventral 

 diameter. Antapical horn cylindrical, curved to the left in a slight gradual 

 curve, apparently twisted, terminating in three acute spinules. 



