FIGURES 1 - 5 



Fig. 1. Ceratium praelongum (Lem.) Kof. A, ventral view of specimen from station 

 31, Caribbean Sea; B, left lateral view of same; C, specimen from station 16, Sargasso Sea; 

 D, heavy-walled individual from station 33, Caribbean Sea. 



Fig. 2. Ceratium cephalotum (Lemm.) Jorg. A, specimen from station 91, near 

 Samoa; B, from station 132, off California; C, from station lb, warm North Atlantic. 



Fig. 3. Variation in C. gravidum Gourret. A, from station 151, equatorial Pacific; 

 B, from station 131, off California; C, from station 75, southeast Pacific; D, from station 

 149, east of Hawaii; E, from station 48, north Of Easter Island; F, from station 107, near 

 Guam; G, from station 91, near Samoa; H, from station 32, Caribbean Sea, showing autot- 

 omy of antapical horns; I, from station 81, east of Tuamotu Islands; J, from station 140, 

 Hawaii; K, from station 19, Sargasso Sea; L, from station 97, near Phoenix Islands; M, ' 

 from station 15, warm Atlantic; N, from station 26, Atlantic North Equatorial Current; 

 O, from station 108, near Guam. 



Fig. 4. Variation in C. gravidum Gourret. P, from station 22, Atlantic North 

 Equatorial Current; Q, from station 18, Sargasso Sea; R, from station 55, south of Easter 

 Island; S, from station 99, north of Phoenix Islands; T, from station 37, Pacific Panama 

 area; U, from station 81, east of Tuamotu Islands. 



Fig. 5. Ceratium digitatum Schutt. A, variety rotundatum Jorgensen from station 

 52, south of Easter Island; B, same from station 54, south of Easter Island; C, right 

 lateral view of typical C. digitatum Schutt from station 25, Atlantic North Equatorial Cur- 

 rent; D, ventral view of same specimen; E, specimen with unusually long left antapical 

 horn from station 105, northeast of Guam. 



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