1910] | TWISS—PROTHALLIA OF ANEIMIA AND LYGODIUM 17g 
_ SEX ORGANS 
The general course of development in both antheridia and arche- 
gonia does not differ from that in the Polypodiaceae. 
The first wall of the antheridium is not, as reported, always flat, 
but may be so concave as to touch the basal wall. 
The number of sperms is large. 
The archegonia have two neck canal nuclei. 
Conclusions 
There is nothing in the formation of the antheridium or in the 
unequal lobing of the prothallium that can be considered character- 
istic of the genera. 
The fact that the rhizoid is not produced as a result of the first 
division of the spore has not yet been reported for other Filicales, 
and may possibly be peculiar to the Schizaeaceae. 
The large number of sperms produced, the occasional stalk of 
the antheridium, and the frequent occurrence of two prothallial 
filaments from the spore, are characters which would place the 
Schizaeaceae with the more primitive families of the Filicineae. : 
I wish to express my thanks to Dr. Joun M. CouLTer, at whose 
Suggestion this work was undertaken, and to Dr. CHARLES J. CHam- 
BERLAIN for his kind direction and criticism. . 
THE UNIVERSITY oF CHICAGO 
LITERATURE CITED 
I. Bauxe, H., Entwickelungsgeschichte des Prothalliums bei den Cyatheaceae, 
verglichen mit derselben bei anderen Farrenkriutern. Jahrb. Wiss. Bot. 
10:49-116. pls. 6-10. 1876. : 
- ——-~-, Beitrige zur Keimungsgeschichte der Schizaeaceae. Jahrb. Wiss. 
Bot. 11:603-650. pls. 38-41. 1878. 
, Zur Kenntniss der sexuallen Generation bei den Gattungen Platy- 
cerium, Lygodium, und Gymnogramme. Bot. Zeit. 36:753-760, 769-780. 
1878. 
4. ———., Aus dem sulle a von Bauke. Beilage zur Bot. Zeit. 
38: pls. 1-6 (following p. 44 
5. Brinrorp, R., Development * oe sporangia of Lygodium. Bor. GAzETTE 
44:214-224. 1907. 
