Box— Vol. I.] CAMPBELL— NATAS AND ZANNICHELLIA. 59 



SUPPLEMENTARY NOTE. 



Since the foregoing paper was completed I have procured 

 a copy of Hofmeister's paper (1861), in which he gives a 

 somewhat extended account of the development of Naias 

 major and a less complete description of the embryo of 

 Zannichellia. In both cases he figures and describes cor- 

 rectly the earliest phases of the embryonic development, 

 including the enlarged suspensor cell, but the details con- 

 cerning the embryo-sac and the later stages of the embryo 

 are very incomplete. No details are given as to the arrange- 

 ment of the tissues in the older embryos, nor does he seem 

 to have noted the absence of a root-cap in Naias. 



