62 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I40 



l()liO 



Fig. 3. — XSC 1-4-a. Increments for 1938, 1939, part of 1940. Complex 

 nature of cambial activity, shifting localized activity ; interior lens ; double over- 

 lapping lenses. 



Fig. 4.— XSC 3-1-a. The increment for I939- Multiplicity and partial gls. 

 Sequence as follows: compound dL; msce, the chief gl; msL; sL overlapping 

 the msL. 



