JEFFRKY. — AHAUCARIOXYLON TYPE. 539 



ones, as a result of tlie had condition of preservation of his materiah^^ 

 Figures e and/, Phite 4, make this prohahihty practically a certainty. 

 Figure <' ilhistrates the transverse view of Aidurarioylon nove- 

 boraccitsc from the Raritaii Cretaceous of Staten Ishind.^* The 

 trachcids in contact with the rays are apparently distinguisjied by 

 their very thick walls. Figure/, which represents a longitudinal view 

 of the same piece of lignite, makes it clear that the apparently thick 

 walled trachcids are in reality only trachcids more or less occupied 

 by a plugging exudation from the rays. 



Although a general statement as to the inferences to be drawn from 

 the scries of articles, of which this is the first, will appropriately appear 

 in connection with the last of the series, it is apposite and necessary 

 to point out the particular conclusions to be derived from the observa- 

 tions recorded here. It is clear that there are certain definite struc- 

 tural relations between the Araucarian woods now in existence and 

 those no longer living. In general the structural features of the 

 ]\Iesozoic Araucarioxyla are strongly retaineil in the cone axis, and 

 the root of living species. They are less strongly retained in the vege- 

 tative stem. In the case of the latter, ancestral features may reappear 

 in the first annual ring of axes of unusual vigor or as a result of injur}^ 

 Injuries to the root result in the recall of more ancient features than 

 those which can traumatically be recalled in the stem. Further it is 

 clear that the comparative developmental and experimental study of 

 living Araucarian conifers is of the greatest value and significance in 

 connection with the accurate diagnosis of fossil forms. A comparison 

 of living with extinct forms, so far as the points considered in this 

 article are involved, shows that certain Mesozoic woods, which have 

 been referred by Seward, Lignier and the present writer to the Arau- 

 cariineae, in reality have that systematic affinity and are not as has 

 been recently suggested by Gothan, the woods of Abietirieous Conifers. 



Conclusions. 



1. The ancestors of Araucaria and Agathis were characterized by 

 the possession of wood parenchyma. 



2. They likewise had strongly pitted rays. 



3. The possession of these two features is (juite inconsistent with 

 their derixation from Conlaitean ancestry. 



13 Op. cil.. pi. 17. 



14 Hollick and JefTrey, Cret. Coniferous Remains, Staten Island, Mem. X. Y, 

 Bot. Garden, 3, pi. 21. 



