No. 508] STUDY OF VASCULAR ANATOMY 233 



of commonly accepted principles of reduction and adhe- 

 sion. Further, it has recently been discovered that the 

 leaves of the ancestral pines (Prepinus) had the same 

 cryptogamic type of centripetal wood-bundles, which are 

 found in the Cordaitales, universally regarded as the 

 Paleozoic stock to which the conifers as a whole are most 

 nearly allied. There is further evidence of the antiquity 

 of the Abietineous or pine tribe based on important ex- 

 perimental data and on the origin of coniferous pitting, 

 which need not be entered upon here. If, in accordance 

 with the facts very briefly indicated above, we cast up our 

 phylogenetic balance by double entry for Pinus, we find 

 it on both sides overwhelmingly in favor of the superior 

 antiquity of the Abietinese, or pines, as compared with the 

 Taxinese, or yews. It would take much too long to cast 

 even hastily the balances for the remaining tribes of 

 conifers and in the case of those at present mainly or 

 wholly confined to the southern hemisphere the data are 

 as yet not complete. Even though the books are not yet 

 ready to be opened for the final judgment, the results of 

 recent morphology on both the gametic and sporophytic 

 sides make it clear that the conifers, contrary to the con- 

 clusions of the old superficial morphology, are a series 

 of reduction and not one of progression and that their 

 most complicated forms are consequently the oldest and 

 those of simplest guise the most modern. 



One of the most striking confirmations of the truth of 

 the theory of organic evolution is found in the recapitula- 

 tionary phenomena of animals. The colt, for example, 

 in the course of its individual development passes 

 through the phases of progressive loss of digits, presented 

 geologically by the equine stock from the Mesozoic to the 

 present. The young mammal in its earlier stages ot 

 ontogeny possesses the gill arches and the segmented 

 musculature of the fish. In the principle of recapitula- 

 tion presented so clearly in the development of animals, 

 our zoological brethren may fairly claim that on their side 

 of the house the truth of evolution is declared by the 



