EXPLANATION OF PLATES. 



Plate 1. 



Fig. 1. Lagena lateralis. X 125. a, front view by transmitted light; b, apertural 

 view; c, front view; d, side view. 



2. Lagena collaris. X 125. a, front view; 6, same by transmitted light; c, aper- 



tural view. 



3. Lagena Ixvis. X 65. a, front view; b, side view; c, apertural view. 



4. Lagena gracillima. X 65. a, front view; 6, apertural view. 



5. Lagena elongata. X 35. a, front view; b, apertural view. 



Plate 2. 



Fig. 1. Lagena Isevigata. X 65. a, front view; b, apertural view; c, front view by 

 transmitted light. 



2. Lagena ovum. X 125. a, front view; b, same by transmitted light; c, aper- 



tural view. 



3. Lagena clavata. X 125. a, front view; b, apertural view. 



Plate 3. 



FigB. 1-3. Lagena sacculus. 1. Form with slight development of keel X 65. a, 

 apertural view; b, front view; c, same by transmitted light. 



2. Form with medium keel X 65. a, apertural view; 6, front view; c, same 



by transmitted light. 



3. Form with broad keel X 125. a, apertural view; b, front view; c, same by 



transmitted light. 



Plate 4. 



Fig. 1. Lagena felsinea. X 75. a, front view; b, same by transmitted light; c, aper- 

 tural view. 



2. Lagena globosa. a, front view, X 75; b, apertural view, X 75; c, optical sec- 



tion, X 40. 



3. Lagena ampulla-distoma, var. cribrostomoides. a, front view, X 90; b, basal 



view, X 90; c, view of aperture, X 300. 



4. Lagena hispida. X 150. a, front view; b, apertural view. 



5. Lagena hispida. X 90. a, front view; b, apertural view. 



Plate 5. 

 Fig. 1. Lagena hispida. X 90. 



2. Lagena hispidula. X 90. a, front view; b, apertural view. 



3. Lagena hispidula. X 90. 



4. Lagena punctulata. a, front view, X 90; b, apertural view, X 90; c, portion 



of surface, X 300. 



5. Lagena hystrix. a, front view, X 90; b, apertural view, X 90; c, portion of 



surface, X 300. 



Plate 6. 



Fig. 1. Lagena squamosa. X 125. a, front view; b, apertural view. 



2. Lagena hexagona. X 65. a, front view, b, apertural view in outline; c, de- 



tail of aperture. 



3. Lagena hexagona. X 125. a, front view; b, apertural view in outline. 



4. Lagena hexagona, var. scalariformis. X 125. 



Ill 



