296 University of Calif ornia Publications i)i Zoology. [Vol. 8 



wide apical 1' of Spiraiilax. I iiieline to the latter alternative, 

 for a widening of this nature may be seen in apical 1' of Gonyau- 

 lax triacantha. Fission line as in Gonyaulax. Surface heavily 

 pitted. The type species is G. jolliffei (Murray and Whitting) 

 Kofoid. 



Spiraulax jolliffei (^Murray and Whitting) Kofoid 

 PI. 19. figs. 1-5. 



Gonyaulax joUiffei Murray and Whitting (1899). p. 324, pi. 28, figs. 



la, b. 

 G. joUifei, Schroder (1900), p. 17. 

 G. jolifei, Karsten (1907), pp. 255, 257, 473. 



Diagnosis : A stout species, body very broadly and somewhat 

 irregularly fusiform, of medium size, epitheca and hypotheca 

 subequal, subconieal, apex truncated, distal end of girdle dis- 

 placed thrice its width, plates 4', !<', 6", 6, 6'", IK l'"\ girdle 

 lists low, surface coarsely pitted, antapex terminating in a sym- 

 metricalty located, stout, acute, solid, horn. 



Dkscription: The body is very broadly fusiform, its length a little 

 less (1.8) than two transdiameters. Apical horn 0.5 trausdiameter in 

 altitude. Apex quite pointed. Epitheca middorsally almost equal in alti- 

 tude to hypotheca, both subconieal, usually less rotund than figured by 

 Murray and Whitting (1899), the sides somewhat deeply concaved, espe- 

 cially the left anterior and right posterior, and slightly swollen in the 

 right anterior and left posterior faces. Murray and Whitting figure 

 an unusually rotund specimen. Girdle section nearly circular. 



The girdle is median, descending, displaced distally thrice its own 

 width, not overlapping, very deeply impressed (0.8 of its width) with 

 heavy overhanging ridges of thecal wall or with low lists with close-set 

 ribs. The ventral area (pi. 19, fig. 5) is very slightly sigmoid, laterally 

 compressed to a narrow slit between the ends of the girdle. It expands 

 posteriorly into an elongated elliptical area 2 furrow widths across and 

 3 to 4 in length, depending upon the elongation of the antapex. 



The theca (pi. 19, figs. 1-3) consists of the following plates: 4', i", 6", 

 6, 6'", IP, 1"". Of the four apicals three are large ones. I', 2', and 3' 

 and one, 4', a small triangular one above the right intercalary. Murray 

 and Whitting find but three plates. The scarcely truncated apex appears 

 to belong to plate 1' and to be closed by a minute translucent closing 

 platelet {cl. pi.) attached at the tip of the plate to the membrane closing 

 the notch. Apical 1' bears on its ventral face at the edge of the apex 

 in the midventral line a rounded notch {n., pi. 19, fig. 3) which is a thin, 

 rather than open region in the wall and recalls the similar region in 

 certain species of Peridiniitm. I have not found it in the genus Gonyau- 



