FIGURES 64-67, and PLATES I-A, I-B, and 1-C 



Fig. 64. Acanthogonyaulax spinifera (Murray and Whitting) Graham. A, separated 

 plates of the ventral area and adjacent regions; B, ventral view of specimen from station 48; 

 C, antapical view of specimen from station 46; D, diagram of undissected ventral area and 

 first three precingular plates; E, apical view of specimen shown in C; arrows indicate posi- 

 tions of girdle sutures. Magnification: x 470. Symbols: apl-ap3, first to third apical plates; 

 as, anterior sulcal plate; i, intercalary sulcal plate; la, left accessory sulcal plate; Is, left 

 sulcal plate; p, flagellar pore; pi, posterior intercalary plate; pol, po2, po6, first, second 

 arid sixth postcingular plates; prl-pr4, pr8, pr9, first to fourth, eighth, and ninth precingular 

 plates; ps, posterior sulcal plate; ra, right accessory sulcal plate; rs, right sulcal plate; 

 vp, ventral epithecal pore. 



Fig. 65. Acanthogonyaulax spinifera (Murray and Whitting) Graham. Ventral view 

 of specimen from station 48. Magnification: x 470. 



Fig. 66. Spiraulax kofoidii new name. A, diagram of ventral area undissected; B, 

 separated sulcal plates presenting their broadest aspects; sculpturing not shown on ps; C, 

 right lateral view of entire specimen from station 48; D, antapical view of same; E, apical 

 view of same; arrows indicate position of girdle sutures; F, antapical view of sixth girdle 

 plate showing the membrane which lies against the cingular list; G, ventral view of specimen 

 shown in C. Magnification: x 340. Symbols: a, anterior intercalary plate; ant, antapical 

 plate; apl-ap4, first to fourth apical plates; as, anterior sulcal plate; gl-g6, first to sixth 

 girdle plates; i, intercalary sulcal plate; 11, left sulcal list; Is, left sulcal plate; p, flagellar 

 pore; pi, posterior intercalary plate; m, rabbet membrane; pc, posterior cingular list; pol- 

 po6, first to sixth postcingular plates; prl-pr6, first to sixth precingular plates; ps, posterior 

 sulcal plate; ra, right accessory sulcal plate; rl, right sulcal list; rs, right sulcal plate; va, 

 ventral area. 



Fig. 67. Ceratium pavlllardii Jorgensen from station 67. A, apical view of right side 

 of body at level of girdle showing end of posterior girdle list, curvature of body at lateral mar- 

 gin, and curvature of horn trough; B, apical platelet; C, ventral view of entire specimen; D, 

 third girdle plate in apical view; E, antapical view of fourth girdle plate; F, distal end of 

 third girdle plate; G, ventral view of body; plates of ventral area not indicated; body pores 

 shown on only part of body; H, dorsal view of body; only few body pores shown; I, four plates 

 of ventral area. Magnification: C, x 50; other figures x 340. 



Plate I-A. Details of skeletal structure of P. depressum . Ventral area and adjacent 

 regions. Magnification: x 400. (Of. fig. 17.) 



Plate I-B. Details of skeletal structure of P. depressum . Detail of ventral area. 

 Magnification: x 730. (Cf. fig. 18.) 



Plate I-C. Details of skeletal structure of p. depressum. Detail of apex. Magnifica- 

 tion: X 670. (Cf. fig. 15.) 



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