566 Slopes . — On the Double Nature of the Cycadean Integument . 
On bringing together recent work on this subject as I have attempted 
to do, it appears to me that it unites in supporting the conclusion that in 
a Lagenostoma with its cupule we see the morphological equivalent of a 
Cycadean ovule with its complicated integument representing the inner 
and outer fused. A consideration of the envelopes of the two seeds 
together thus throws light upon each, and upon the origin of integumentary 
structures in general. 
March io, 1905. 
