L48 G. />'. Wieland — Aim riant Fossil Cycads. 



Fig. 7. 



X/5 



Fig. 7. Cycadeoidea Maebridei (?). 



Four characteristic subtransverse to sublongitudinal sections of seeds con- 

 taining embryos from as many different thin sections (Nos. 762-765) cut from 

 one of the various strobili of the Minnekahta cycad trunk Y. S. No. 1<51 : 

 all x 15. 



A. — Subtransverse section. Passes near the •' shoulder" of the seed as 

 indicated by the apical ribs on the upper side, but below the radical since 

 the two cotyledons with their bundles (b) plainly appear. In the upper 

 cotyledon which must be cut near the cotyledonary node but four bundles 

 are traversed, approach to the maximum number of five or six lamina bun- 

 dles appearing on the lower or more basal side. 



The somewhat convolute prolongation above is most readily explained as 

 a remnant of proembryonic tissue exactly like that persisting or but slowly 

 made over into the true embryo tissue in the very similar dicotyledonous 

 embryo of Ginkgo. 



