154 0. It. Wu land — American Fossil Cycads. 



oase. Others who have seen the sections are at. least certain 

 that the tissue is not endospermous ; and to the objection that 

 a proembryonic tissue would not be likely to thus occupy quite 

 all of the nucellar cavity it is replied that such a condition is 

 in reality only one of degree, and that it is readily conceivable 

 as having been present in Cretaceous gymnosperms. Though 

 it is of interest that conformably to the lesser degree to which 

 the embryos shown in figure 7 fill up the nucellar cavity as 

 compared with those of figure 6, far more distinct traces of 

 endosperm are present. 



The sections, which may be seen at the Yale Museum, are 

 uot only being constantly added to, but meanwhile receiving 

 careful attention and comparison, and it is intended to give fea- 

 tures displayed the best possible illustration. Meanwhile ink 

 drawings of various seeds are appended in the present text 

 figures 7 and 8 illustrating the strobili of Yale Cycad 131. 

 This trunk is one of those referred to 0. Wielandi by Pro- 

 fessor Ward, but cannot be of that species as represented by 

 trunks 77, 393, and various other specimens constituting a dis- 

 tinct and unmistakable group. Trunk 131, which bears stro- 

 bili with not infrequent finely conserved embryos — indeed 

 quite the best so far known — may be provisionally referred to 

 C. Macbridei. The chief vegetative differences from C. Wie- 

 landi are exhibited by the sections through the cortical paren- 

 chyma, showing the leaf traces and the leaf bases of both to be 

 of much larger size than in the C. Wielandi trunks, while the 

 main differences in testal development are exactly noted in the 

 legends of the respective figures, 4 C, 7, etc. 



The present drawings all show the position of the young 

 embryo bundles to agree with that seen in both Bennettites 

 Gibsonianus and £. Morierei, as shown by the scheme of the 

 embryo bundle pattern, figure 9, which must closely approxi- 

 mate the true form. From this it is evident that a pattern a 

 little more reduced than that of the living cycads, but not so 

 much as that of conifers, is present. In fact, the bundle pat- 

 tern is the same composite one seen in Ginkgo biloba, to the 

 general form and structure of the entire embryo of which 

 there is a very close analogy, extending to the occasional occur- 

 rence of three cotyledons instead of the normal dicotyledonous 

 condition. 



Finally, the fact that seed and embryo of these fossil cycads 

 are of the most generalized gymnospermous type can escape no 

 one ; while the retention of pronounced cycadofilicinean fea- 

 tures further favors inclusion in the Cycadales. Though for the 

 present letting classifications evolve themselves as they may, 

 it is most interesting to observe that not only were the primi- 

 tive seed characters of the Cycadeoideae little obscured by 



