2 5 
Anatomy of the Ophioglossaceae. 
passes through the posterior portion of the embryo proper. Still further 
forward (d) only the anterior and upper edge of the suspensor is cut by the 
section, the main part of which passes through the hypobasal tier of the 
embryo. The section in E traverses the anterior portion of the hypobasal 
tier, the cells bounding the lower surface of which had the characteristic 
appearance of the absorbent epithelium of the foot. The arrangement of the 
cells in the region marked with a cross suggested that the section here 
passes through the apex of the primary root. A section a little further 
forward (f) shows (immediately above the presumable position of the root- 
Text-fig. 5. Outline figures of a number of longitudinal sections of the upper portion of a 
prothallus bearing a young plant and an embryo of intermediate age. The suspensor of the plant 
is seen at s in e, while the corresponding archegonium is seen at ar. j 1 , first tier of suspensor of 
the intermediate embryo ; s 2 , second tier of suspensor ; e, base of embryo proper ; x in e marks 
position of the apex of the root ; tr in F the tracheides developed in the stele ; x in G the position of 
the apex of the stem. 
apex) a desmogen strand, in which a few short tracheides are lignified. 
Still further forward (g) the apical region of the shoot marked with a cross 
is cut through. The portion of the next two sections marked off by the 
dotted lines corresponds to the young cotyledon or first leaf bent closely 
over the stem-apex. 
The detailed structure of four sections of this embryo is shown in 
Photos. 6 - 9 . It would have been difficult to make detailed drawings of this 
poorly stained embryo without either over-emphasizing the indications 
of segmentation which it affords, or on the other hand missing these indica- 
