INTRODUCTION This Index is dedicated to the late Dr. Frank Springer, eminent world authority on Paleozoic crinoids and former honorary Associate in Paleontology in the United States National Museum. It was Doctor Springer’s earnest desire that a bibliography of all fossil Pelmatozoa should be made available to students, and it is in recognition of this wish that the present work covering the Paleozoic species was completed. The Index is based on a working catalogue of genera and species assembled for Doctor Springer by his daughter Ada, now Mrs. Warren B. Davis of Philadelphia. This covered the earlier literature and was supplemented from time to time until about 1915 by the work of Doctor Springer’s secretary. Since his collection, library, and other scientific matter came into possession of the Smithsonian Institution upon his death in 1927, the bibliography has been brought up to date by Miss Moodey. All citations in the above card catalogue have not been recorded here, selection having been made of those considered most essential; others are largely included in the works cited, and the complete set of references is preserved in the department of geology in the United States National Museum, where it may be consulted by those interested. One object of the work is to place on record, as far as possible, the correct geological and geographical occurrence of the species, a practice sadly overlooked in the early publications, particularly those of foreign countries. The Pelmatozoa, comprising the cystoids, blastoids, and crinoids, have . . .