76 



IT. F. Pieid — Studies of Miiir Glacier. 



sectioned in many places between adjoining fibers, as in p, figure 

 4 ; and in figure 5, .r, it is seen that neighboring cells communi- 

 cate with each other by a canal or aperture in the center of each 

 wall of the pit. A limiting lamella sometimes, if not always, 



ik. nil- h. i.3. U. 



Figure 4 — Longitudinal Section of Wood from the hurled Forest. 



m r =^ Medullary ray ; p = Pit-cavity ; d = Deposit in cell of medullary 

 ray ; op = Aperture of pit ; bj)^= Bordered pit ; tl,t2,t3,t4 =Tracheides. 



occurs in the fresh wood of coniferous trees, stretched across the 

 cavity of the pit. This serves as a screen to block the direct 



