PREFACE. 
xiii 
toward the structure and classification of the genera were made by Zittel, 
(Ehlert and Waagen, and communications of no little importance relating to 
structural characters of genera and species, appeared from all quarters of the 
scientific world. 
The multiplicity of these communications is indicated in part by the biblio¬ 
graphic tables presented in this volume; they also show the wide-spread inter¬ 
est in the Brachiopoda, not only among students of biology, in their structure, 
morphology and taxonomy, but among geologists, in their value as stratigraph- 
ical indices. American students have heretofore labored under a disadvantage 
in the irregular diffusion of the literature of the Brachiopoda. Much of the 
European literature is inaccessible except to those working in the vicinity of 
extensive libraries; the American literature is so scattered through scientific 
periodicals, proceedings of various societies, etc., as to be frequently inaccessible. 
Furthermore, while the more general treatises of Zittel and (Ehlert may be 
in the hands of many, the greatest of all works upon the subject, that of Thomas 
Davidson, is beyond the reach of but a very few. 
With this volume, therefore, is presented, especially to American students, the 
first part of “An Introduction to the Study of the Genera of the Palaeozoic 
Brachiopoda,” a work not conceived upon the plan of any of its predecessors, 
but designed to set before the student the present condition of our knowledge 
of these genera, with such discussions and illustration as will serve most 
clearly to indicate what progress has been made in our knowledge of these 
organisms and in what directions much still remains to be done. 
In the preparation of this work every effort has been made to bring under 
close and careful scrutiny all obtainable material representing the Brachiopoda. 
The collections of no single institution or individual could furnish the speci¬ 
mens requisite for this undertaking, and recourse has been had to all sources of 
material within reach. The collections of private individuals as well as of 
public institutions have been placed at the disposal of the work, and but for 
such aid it could not have been presented in a creditable form. 
My acknowledgments are especially due to Sir William Dawson, Principal 
of McGill University, Montreal, Canada, for specimens and valuable informa- 
