FIGURES 15 and 16 



Fig. 15. A, Ceratium compressuin Gran from station 61, southeast Pacific. 



B-C. Ceratium filicorne Nielsen. B, from south of Easter Island, station 57; C, 

 from near Samoa, station 93. 



D-E. Ceratium axiale Kofoid. D, from off Japan, station 112; E, from station 63, 

 southeast Pacific region. 



F-G. Ceratium aultii n. sp. F, from station 72, off Peru; G, from station 151, 

 eastern warm Pacific region. 



H-I. Ceratium svmmetricum PavUlard. H, variety orthoceros Jorgensen, from sta- 

 tion 43, north of Easter Island; I, variety svmmetricum Pavlllard, from station 153, eastern 

 warm Pacific region. 



J-L. Variety coarctatum Pavillard. J, from station 67, southeast Pacific region; K, 

 from station 153; L, from station 57, south of Easter Island. 



I M-N. Ceratium euarcuatum Jorgensen. M, from station 16, warm Atlantic; N, from 

 station lb, warm Atlantic. 



Fig. 16. A-K. Ceratium arietinum Cleve. From station 130, off California. B, from 

 station 73, off Peru (answers to southern form of bucephalum of Peters); C, from station 61, 

 southern end of southeast Pacific region (also corresponds to southern form of bucephalum) : 



D, from station 127, cold North Pacific (corresponds to Pacific northern form of bucephalum) : 



E, specimen from same sample showing the more typical arietinum form; F, from station 46, 

 eastern tropical Pacific (corresponds to subsp. gracilentum of the Atlantic); G, from station 

 148, between United States and Hawaii (small arietinum type); H, from station 6h, North Sea 

 (corresponds to C. bucephalum of the North Atlantic); I, from station 130, off California; J, 

 from station 110, between Japan and Guam; K, subspecies gracilentum of Atlantic, from sta- 

 tion 22, North Equatorial Current. 



L, Ceratium petersii Nielsen. From station 61, southern end of southeast Pacific re- 

 gion. 



M-P. Ceratium azoricum Cleve. M, from station 44, west of Galapagos; N, from 

 station 110, between Japan and Guam; O, from station 127, cold North Pacific; P, from sta- 

 tion 6, off Ireland. 



Q-T. Ceratium declinatum Karsten. Q, variety declinatum from station 15, North 

 Atlantic West Wind Drift; R, from station 67, southeast Pacific region (characteristic of 

 southeast Pacific but found in other regions as well); S, variety maius from station 3, cold 

 North Atlantic; T, variety laticornum from station 13a, cold Atlantic region. 



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