ATWELL: POLAR BODIES IN RICCIOCARPUS 335 
mosomes splitting. Occasionally granules other than those 
appearing at the poles are observed in the cytoplasm, as shown in 
FIG. 5. 
Mottier and Ikeno, who observed true centrosomes in plants, 
report that they are formed from a single body dividing in two. 
In these observations on Ricciocarpus natans the bodies seem to 
appear at once in the polar position with each new division. 
Whether or not they persist in the spermatid after the diagonal 
division and may later become blepharoplasts has been discussed 
by Black (1), Lewis (3), Wilson (5), Woodburn (6), and others. 
This study was not carried far enough to observe these late stages 
in Ricciocarpus natans. 
NORTHWESTERN UNIVERSITY 
EVANSTON, ILLINOIS 
LITERATURE CITED 
1. Black,C.A. The morphology of Riccia Frostii Aust. Ann. Bot. 27: 
SF E-532) O..37, 366 > TORS: 
2. Ikeno, S. Beitrage zur Kenntnis der pflanzlichen Spermatogenese: 
Die Spermatogenese von Marchantia polymorpha. Beih. Bot. 
Centralbl. 15: 65-88. pl. 3 +f. 1903. 
3- Lewis, C. E. The embryology and development of Riccia lutescens 
and Riccia crystallina. Bot. Gaz. 41: 109-138. pl. 5-9. 1906. 
Mottier, D. M. The centrosome in cells of the gametophyte of 
Marchantia. Proc. Ind. Acad. Sci. 1898: 166-168. 1899. 
5. Wilson, M. Spermatogenesis in Bryophyta. Ann. Bot. 25: 415- 
457. I9gtt. 
6. Woodburn, W. L. Spermatogenesis in certain Hepaticae. Ann. 
Bot. 25: 299-313. pl. 25. 1911. 
- 
Explanation of plate 8 
All drawings were made with the aid of a camera lucida. A Spencer microscope 
was used with Rema aH objectives, 1.5 mm. oil immersion, 3 mm., 16 mm., and 
compensating oculars 6 X and 12 X. Fics. 1 and 2 were drawn at stage level 
and all others at table level. 
IG. 1. Young antheridium. One segment showing three nuclei with polar 
,600 
Fic. 2, Older antheridium. XX I50. 
1G.3. Two rest in early prophase. The chromatin of the nucleus is seen in an 
irregular mass. X 3 
