KOFOID AND SWEZY: UNARMORED DINOPLAGELLATA 235 



(1878). Stein's species differs in its proportions and in the lack of a red pig- 

 ment si)ot. Tlie ventral face of Perty's form lias not been figured, hence that 

 part of the organism cannot be compared with G. vorticella. Until further 

 work has established its definite morphological characters, this form must be 

 considered as a doubtful species not identifiable with existing data. 



Gymnodinium monas (Ehrenberg) 



Peridinium monas Ehrenberg (]840), p. 201; (1845), p. 18. 



Hcteraiclacus ? monas Diesing (1850), p. 101. 



Heteroaulux f monas Diesing (1866), p. 95. 



Peridinium monas, Claparede and Laehmann (1858-61), p. 406. 



P. monas, Maggi (1874), p. 118; (1880a), pp. 9, 13; (1880&), pp. 309, 313. 



P. monas, Stein (1878), p. 60. 



P. monas, Savillo-Keut (1880-82), p. 444. 



Ehrenl^erg (1840) has described as Fcridinium monas an organi.sm which 

 Saville-Kent (1880-82) considered as possibly identical with Gymnodinium 

 marinum. Ehrenberg 's description, without figures, hardly furnishes an 

 adequate basis for the systematic allocation of this small form. He has de- 

 scribed it as very small, obtuse, withoiit horns, and remarkably social, its 

 diameter 43a^ and occurring in the Baltic Sea. The absence of a theca would 

 remove it from the genus Peridinium , but the lack of further data leave it 

 permanently indeterminable. 



Gymnodinium multilineatum sp. nov. 



Plate 5, figure 59 ; text figure Y, 18 



Diagnosis.- — A rather large species, with synnnetrical, Ijroadly fusiform 

 body, apex rounded, antapex more contracted, bullet-shaped, its length about 

 2 transdiameters, both with minute points; girdle slightly displaced; surface 

 with fine striae, al)Out 50 on one face; colorless; nucleus central. Length, 108/*. 

 Pacific off La Jolla, California, July, August. 



Description. — Tlie body is broadly fusiform, perfectly symmetrical, circular in cross-section, 

 its length 2.25 transdiameters. The epicoue is about 1.66 of the length of the hyjjocone, and 0.9 

 transdiameter in length, rotund ellipsoidal, apex broadly rounded, with a minute apical point. 

 The hypocone is 1.35 transdiameters in length, shaped like the nose of a bullet, the antapex 

 contracting symmetrically to a sharp point. 



The girdle is 0.4 of the total length of the body from the apex, almost in transverse plane, 

 both proximally and distally the ends deflected for less than their width posteriorly. The distal 

 end in one individual was displaced posteriorly about its own width witli almost no overhang 

 of the proximal end over the distal one. The transverse furrow is deeply impressed, and exca- 

 vated below the sharp-edged lips. The flagellar pore of the transverse flagellum is an elliptical 

 opening just posterior to the proximal end of Ihe furi-ow on the left side of the longitudinal 

 furrow. The transverse flagellum is a thin, iuui-o\v I'ibboii almost completely encircling the 



