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Po rar, eSt Sa ee. 
1913] CHAMBERLAIN—MACROZAMIA MOOREI I5I 
the tube and none of the peculiar basal haustoria which charac- 
terize the pollen tubes of Ceratozamia. 
The condition of the male gametophyte when the pollen is shed 
is remarkably uniform in the family, no exception to the three- 
celled stage having as yet been demonstrated. IkeNo found this 
condition in Cycas revoluta, and Miss Frances G. SmitH found it in 
Encephalartos villosus. I have observed it in Dioon edule, Cerato- 
zamia mexicana, Microcycas calocoma, Zamia floridana, Bowenia 
spectabilis, Macrozamia Miquelii, M. spiralis, and Stangeria para- 
doxa; so that it occurs in all the genera. The behavior of the 
three cells is also similar, the prothallial cell pushing up into the 
stalk cell in all the genera, with the possible exception of Cycas. 
Since the structure of the pollen grain is so uniform in the 
cycads, it would be interesting to know just what the structure is 
in fossil Cycadales and Bennettitales. A more extensive develop- 
ment of prothallial tissue and a comparatively slight development 
of the pollen tube or haustoria might be anticipated. 
The female gametophyte 
Early in November, when the ovulate cones have attained a 
length of 78 cm., the female gametophyte has reached its full size, 
but by no means its full density. The archegonia, generally 4-6 
in number, are a little more than 3 mm. in length and are becoming 
filled with protoplasm and foodstuffs. The ventral canal nucleus 
has not yet been cut off and the archegonial chamber has just 
begun to develop. At the fertilization stage, most of the cells of 
the female gametophyte contain large starch grains; the rest 
contain tannin. The archegonial chamber is the deepest ever 
noted in a cycad, the average depth being about 1.8 mm., so that 
the depth is nearly two-thirds as great as the length of the arche- 
gonium (fig. 9). 
The embryo 
The earlier stages in the development of the embryo are not 
available, but arrangements have been made to secure them. The 
earliest stage in our material is shown in fig. 9. At this stage 
Macrozamia Moorei differs from Dioon edule, Ceratozamia mexicana, 
and Zamia floridana, but agrees with Cycas revoluta and perhaps 
