Ftirther Notes on Seed Structures. 135 



by strobili, as it revealed three entire and two nearly entire 

 axillary ovulate strobili, with bnt two of the five comple- 

 mentary leaf-bases ; and with the cones thus located an equa- 

 torial armor section was at once cut through the summits of 

 three adjacent ovulate cones. In all the cones the mineraliza- 

 tion is, after the manner of siliciiication, not so distinct as 

 calcification, but yet excellent, and nearly every seed contains 

 a mature embryo, not so well conserved as those of Yale trunk 

 131,* but yet showing quite satisfactorily the character of the 

 embryonic tissues. Especially valuable for purposes of com- 

 parison are these embryos, because little shrunken, and with 

 the epidermal cells nearly always more or less distinct. Other 

 sections of Cycadeoidea embryos showing more of detail we 

 have in abundance, but none more beautiful than these. 



In continuing the elaboration of material for the volume on 

 the Taxonomy of the American Fossil Cycads, now in course 

 of preparation under the auspices of the Carnegie Institution 

 of Washington, many new strobili have been cut during the 

 past year. Also, in addition to the strobili cut from the new 

 Black Hills trunk, I have made seed sections of Bennettites 

 Gibsonianus of the Isle of Wight, and already had at hand the 

 sections of Bennettites Morierei obtained from Professor 

 Lignier as related in my American Fossil Cycads. In short, 

 there has thus been brought together a representation of all the 

 forms so far known; and on the basis of this complete repre- 

 sentation it has been found very desirable to simplify ideas of 

 the structure of the testa in the Cycadeoidese, not alone for the 

 purpose of forwarding present studies, but of making the 

 paleobotanic text on this subject short and satisfactory. 



As is always inevitable in the case of a complex fossil plant 

 structure, the different types of mineralization, in this instance 

 nature's own variation of her staining- and imbedding 

 methods (!), result in slightly different interpretations in the 

 hands of different investigators. What with this factor and 

 different modes of illustration or study of areas and features 

 seldom taken from the same region of a seed, or showing varia- 

 tion of a given region in one and the same seed, it becomes all 

 too easy to suspect greater differences in even a small group of 

 species than actually exist ; while meantime certain salient 

 features are likewise easily overlooked. So it has proven in 

 the case of the cycads, though of simple enough structure on 

 closer study. In order, consequently, to bring out a funda- 

 mentally clear comparison of all the seeds, American as well 

 as European, showing the best testal conservation, camera 

 lucida drawings have been made of longitudinal sections at a 

 * Illustrated in American Fossil Cycads, Plate XXII. 



