THE PLUMULARIDJE. 5 



internodes in all species examined by me. It may run along the front of the stem and branches 

 (Plate XVI, tig. 5) or be buried beneath the accessory tubes and occupy a central or axial position 



i UM-S ANATOMY Ul" I'Ll'Ml'LAKl AN .STEM. 



Fig. I. Stem of Antt-nnularia Iff rant iclta, showing canaliculate*! eu-noaarc. 



Fig. 2. Cross section oi t'mcirli-il sti-m, /<, hydrocladiate tube. 



Fig. ;t. Stem of Plumularia procumbens, showing immersed hydrooladiate tube (after Spencer). 



Fig. 4. Longitudiuiil sect inn ni fascicled stem, showing cross connection hi- 1 WIM-M tubes (ufter Allman). 



FIL(. fi Part of stem of same, slmu mi: " ]nnclicd place." 



Fig 6. Single tube from stem of Tltecncarjnm ni>ti-i<>jilii/Uinn, showing lateral processes. 



in the stem (fig. 3). If the fascicled stem be boiled in a solution of potash, the component tubes 

 can easily IK* separated and traced throughout their length. As a general thing the hydrocladiate 



