EXPLANATION OF PLATE 19 



Spiraulax joUiffei (Murray aud Whitting) Kofoid 



All figures magnified 500 diameters. 



Fig. 1. Diagram of antapical view of hypotheca, showing plates and 

 fission line {f. I.) 



Fig. 2. Diagram of apical view of epitheca showing same. 



Fig. 3. View of right side of theca, showing plates. Apical plates 

 partec^. Seven miles WNW Point Loma, California, November 12, 1904. 



Fig. 4. Dorsal view of same, showing surface structure. 



Fig. .5. Ventral view of same. 



ABBEEVIATIONS 



4-6 — girdle series of plates. 

 l'-4' — apical series. 

 1" — anterior intercalary plate. 

 1"~6" — precingular series. 

 l"'-6"' — postcingular series. 

 IP — posterior intercalary plate. 

 1"" — antapical plate. 



cl. pi. — closing jjlatelet of apex. 

 /'. /. — fission line. 

 g. g. — girdle suture. 

 /(. — ventral apical notch. 

 post. pi. — posterior plate of ventral 

 area. 



Figures drawn by Mrs. Josephine Rigden Michener. 



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