1911] Kofoid: The Genus Gonyaulax. 233 



periods of greatest relative abundance appear to coincide with 

 that of the plankton of semi-tropical facies in November-January. 

 It is also sparingly present in June-September, especially at 

 times of outbreaks of red water. 



Judging from the reported occurrences of this species it is 

 generally rare but widely distributed in tropical waters. It is 

 reported from the Atlantic by Murray and Whitting (1899), 

 and found occasionally, according to Cleve (1901a) as far north 

 as 60° N. It is also reported by Cleve (1901b), and by Karsten 

 (1907) from the Indian Ocean, by Schroder (1900) from Naples, 

 by Entz (1902) from the Adriatic, by Ostenfeld and Schmidt 

 (1901) from the Red Sea, and by Schmidt (1901) from the Gulf 

 of Siam, by Nishikawa (1901) and Okamura (1907) from 

 Japanese waters, and by Zacharias (1906) from the South Pacific 

 oft' Antofagasta, Chili. 



9. Gonyaulax kofoidi Pavillard 



PI. 14, fig. 30 

 Gonyaulax l-ofoidi Pavillard (1909), p. 278, fig. 1. 

 G. globosa Stiiwe (1909). p. 275, pi. 2, fig. 7. Doubtfully assigned 

 here. 

 Di.vGNOSis : A large species with elongated body, tapering 

 apical horn, asymmetrical antapex and prominent left antapical 

 spine, with coarsely porulate longitudinally striate surface. 



Desceiption: Body elongated, length, excluding spine, 1.65 trans- 

 diameters, girdle section subcircular, flattened ventrally. Epitheca 

 exceeds hypotheca its altitude 0.9 to 1.1 transdiameter, conical, with 

 slight angulation on left shoulder, and abruptly changing to a tapering 

 apical horn 0.4 to 0.5 transdiameter in length, 2 to 2.5 girdle widths 

 wide at the base and 1.5 at the truncate apex. Hypotheca with nearly 

 straight sides and obliquely truncate antapex. The oblique postmargin 

 is 0.3 transdiameter in length; altitude of hypotheca 0.75 transdiameter. 



Girdle descending, displaced distally 2 to 2.25 girdle widths, its ends 

 lacking at least 0.5 of a girdle width of completing the circuit. Both 

 proximal and distal ends curve posteriorly. It is deeply impressed, with 

 salient heavy ridges of thecal wall. The anterior plate of the ventral 

 area (pi. 14, fig. 30) indents the epitheca for 1.5 girdle widths, ending 

 in an obliquely truncate margin. The region of the intermediate plates 

 is almost completely buried between the girdle ends. The ventral area 

 curves to the right and in its distal half flares widely, mainly to the 

 right to 3 girdle widths, the wide porulate posterior plate reaching the 

 postmargin. It is guarded on the right side anterior to the distal end 

 of the girdle and on the left, posterior to its proximal end, by a hyaline 

 fin or list, passing posteriorly to the base of the single antapical spine. 



