tors]: HUTCHINSON—PELLIA EPIPHYLLA 143 
I am greatly indebted to Professor Joun M. Courter for sug- 
gestions and criticisms received, and to Dr. W. J. G. LANp, under 
whose direction the work was done. 
UNIVERSITY OF CHICAGO 
EXPLANATION OF PLATES I-IV 
All drawings were made with the aid of the Abbé camera lucida. Original 
magnification of figs. 15, 40, and 50 was 500; of all other figures 1730. The 
reduction in reproduction is one-thir 
Fics. 1-29.—The antheridium of Pellia epiphylia. 
Fics. 1-6.—Longitudinal sections of a young antheridium, such as is elier- 
acteristic of Jungermanniales. 
IGs. 7-9,—Cross-sections of the sam 
Fics. 1o-12.—Cross-sections of shined of Pellia similar t to “those of 
Sphaerocarpus or Marchantiales. 
IGS. 13, 14.—Sections through the stalk (fig. 13) and spermatogenous 
region (fig. 14), the latter illustrating two methods of growth. 
Fic. 15.—A double antheridium. 
Fics. 16-22.—Longitudinal sections of antheridia showing a eisicannent 
similar to that of an archegonium 
Fics. 23-25.—Similar to last, ‘yah the elimination of thé" cap Sas 
Fics. 26-29.—Cross-sections of the same. 
Fics. 30-40.—The archegonium. 
Fics. 30-38.—Longitudinal sections. 
Fic. 39.—Cross-section. 
Fic. 40.—Cross-section of archegonial pocket. 
Fics. 41-50.—Growth structures. 
Fic. 41.—A cuneate apical cell in young gametophyte which has just 
escaped from the spore coat. 
Fics. 42, 43.—Sections of sporeling showing the segmentation of the 
cuneate apical cell; fig. 42, vertical; fig. 43, horizontal section. 
IGS. 44, 45.—Transition forms of apical ce 
Fics. 46-48.—Sections of the lenticular cylindiic apical cell, also showing 
the region surrounding; fig. 46, a transverse vertical section; fig. 47, a longi- 
tudinal vertical section; fig. 48, a marginal longitudinal vertical section, 
showing how the lateral segments produce the wing or lobe. 
Fic. 49.—A section through a region of apical growth. 
1G. 50.—A young sporophyte inclosed by a somewhat massive calyptra 
and the involucre; sterile archegonia on calyptra. 
