74 Miss Agnes Crane — Erohition of the Braehiopoda. 



Beecher, Dall, Douvillee, Deslongchamps (34), Fischer, and the 

 CEhlerts (63), as forming, in many instances, natural connecting 

 links or passage-forms between other genera, and the remaining 

 three were ultimately accepted by Davidson himself in his last 

 posthumous "Monograph on the Recent Braehiopoda" (27). 



He had evidently an almost invincible repugnance to the multi- 

 plication of generic names and definitions. "Were we to indulge," 

 he wrote in 1884, " the system of making genera out of every trifling 

 and unimportant difference, the number would become so great that 

 it would not only confuse the subject, but render the study of the 

 Braehiopoda one of repulsive difficulty " (28). 



The modern school of fin du siecle brachiopodists consider that 

 it is the combination, under one generic name, of species with 

 divergent internal features which perpetuates this confusion. They 

 look upon such forms, as for convenience we call genera, as natural 

 occurrences in nature, not as mere arbitrary scientific abstractions 

 designed for the gratification of those nomenclatorial propensities 

 apparently inherent in mankind since Adam modestly named all 

 creation that was known to him. If a genus comprises an assem- 

 blage of forms of which certain characteristics are universally 

 predicable, it seems but reasonable to conclude that any deviation 

 from the universal rule should form an exception and be placed in 

 another genus. Up-to-date biologists, therefore, prefer to restrict 

 the number of species, regarding many forms of so-called species 

 merely as divergent resultants from age and environment, and 

 consider the erection of " trifling " differences into generic or 

 subgeneric characters as perfectly justifiable, so long as they are 

 found to be permanent features of adult structure (4, 5, 6). 



These minute generic divergences from the original type are 

 justly regarded as so many links in the chain of the generic descent 

 of the race in general, by which they can trace collateral branches 

 with their numerous ramifications. That some of the main lines 

 die out while the collaterals and their respective ramifications 

 continue to be represented, is nothing unusual in genealogical 

 investigations. In other cases the main line persists, as in Lingula, 

 whilst many of the smaller branches of the linguloid stock became 

 extinct and left no immediate descendants. 



Just at present we are willing to admit that the study of the 

 Braehiopoda presents many difficulties to one occupying — like myself 

 — a neutral vantage ground, respecting the older paleeontologists 

 whose valuable labours in many cases alone rendered possible the 

 significant deductions of that New School with whose methods I 

 am in full sympathy. But we must not be deterred by difficulties, 

 however " repulsive " they may be, from the pursuit of truth, and, 

 as students, we must learn to adapt ourselves to the new methods 

 and novel nomenclature, the results of which will in the end clear 

 up the minor questions which still obscure a complete demonstration 

 of the evolution of the Braehiopoda. It is well to remember, as 

 Lowell has well said, that "the foolish and the dead alone never 

 change their opinions." 



