KOFOID AND MICHENER: DINOFLAGELLATES. 283 



Peridinium pacifica, sp. nov. 



A small species resembling P. pdlucidum Bergh but with much displaced 

 girdle and proportionately greater girdle section. Body very broadly pyri- 

 form, contracted to small apex, but with scarcely any differentiated apical 

 horn. Length, excluding spines, 1.08 transdiameters. Epitheca exceeds 

 hypotheca, its altitude 0.76 transdiameter, hemispherical near girdles, con- 

 tracted to conical apex. Ventral notch 1.5 girdle widths long. Hypotheca 

 low, dome-shaped, contracted distally to narrow postmargins. Two equal, 

 solid, subulate antapical spines 1.5 girdle widths in length, 2.5 apart at base 

 and 3 at apex, rise from slight rounded projections. Postmargin with shallow 

 arch. Girdle ascending, displaced 2 girdle widths, scarcely completing the 

 circuit, proximal end posteriorly deflected, furrow not impressed, with low 

 hyaline, non-ribbed lists. Ventral area spreading to the right and reaching 

 postmargin, without lists or spines. Three dorsal anterior intercalary plates. 

 Surface porulate and minutely areolate, with striate intercalary bands 1 to 

 1.5 girdle widths across. 



Length, midbody only, 62 n, total, 66 n', transdiameter, 57 n. 



Sta. 4732. 



Peridinium poucheti, sp. nov. 



A small species with rotund body, short apical horn, short, close set, hollow 

 antapical horns, ascending girdle and indenting postmargin. Differs from 

 P. pallidum Ostenfeld in more rotund body, closer set, shorter antapicals. 

 Differs from P. adriaticum Broch (1910), p. 192, fig. 8, in the same particulars, 

 in less postmarginal excavation, and in greater displacement of girdle. It 

 resembles P. pellucidum Bergh (1881) pis. 15, fig. 46, 47, in form of body but 

 differs from it in greater extent of cavity in antapicals, more displaced girdle 

 and stouter apical horn. Belongs to subgenus Protoperidinium rather than 

 Euperidinium. Body elliptical with short, stout, apical, and slightly developed, 

 partially hollow, subulate antapical horns. Total length 1.6, apical horn 

 0.2, antapicals 0.27 transdiameters. Girdle section circular. Epitheca 

 equals hypotheca in total altitude, broadly hemispherical, contracted to taper- 

 ing apical horn 1.5 girdle widths in height and 0.8 across apex. Ventral 

 notch 1.3 girdle widths in length. Hypotheca subhemispherical, notched 

 about 0.6 girdle width by postmargin. Antapical horns 0.27 transdiameter 

 between centers of bases and 0.37 between tips, tapering subulate, distally 

 formed of solid spines. Girdle ascending, displaced nearly 1 girdle width, 

 not impressed, with ribbed, hyaline lists. Ventral area narrow, straight, 

 with hyaline lists, but no posterior spinules. Surface finely and evenly 

 reticulate throughout. 



Length, 58 fi) transdiameter, 36 ju. 



Sta. 4709. 



