6 SMITHSONIAN INSTITUTION 



All of the specimens so obtained from these widely distributed faunas 

 have been added to the museum collection, thus bringing together, either by 

 way of types or of authentic representative specimens, nearly all the species 

 described by Mr. Clark in his various publications, so that the collection now 

 includes among its 5387 specimens about 350 species from all the oceans, being 

 over 60 per cent of the Recent crinoids known to science. This comprehensive 

 material has formed the basis of Mr. Clark's numerous works on the Recent 

 crinoids, consisting of the first volume of his Monograph of the Existing 

 Crinoids, and 125 other memoirs and papers, including 23 published by foreign 

 authorities. These researches have resulted in the description by the author 

 of 343 new species out of a total of 567 now described, to which will be added 

 upwards of 50 more now under investigation by him; and in the creation of 

 123 out of the 142 known genera. 



As having a special bearing upon my own work it may be noted that there 

 is now contained in this museum collection an assemblage of larval forms of 

 different genera from various areas such as has never been brought together 

 before, some of which have been utilized by me in studies throwing new and 

 important light upon the phylogeny of the fossil forms. From the standpoint 

 which I have constantly maintained, that the fossil crinoids must be studied in 

 connection with their living representatives, the advantage of the free use of 

 such a great collection cannot be overestimated. This has been augmented by 

 the privilege of drawing without limit upon Mr. Clark's vast fund of knowl- 

 edge of the Recent crinoids, as to which I have been in constant communica- 

 tion with him ever since he began his crinoid studies in 1907. For the 

 opportunity of unrestricted access to, and liberty to use, the specimens of this 

 collection I wish to acknowledge my indebtedness to Dr. Paul Bartsch, Curator 

 of Marine Invertebrates in the National Museum. 



At the Museum of Comparative Zoology of Harvard College my status 

 as Associate in Paleontology in former years gave me officially the run of the 

 collections; but the cordial interest in the work manifested by Mr. Alexander 

 Agassiz during his lifetime, and by Mr. Samuel Henshaw, Director of the 

 Museum afterwards, made my studies there doubly enjoyable. Containing as 

 it does the original collections of Wachsmuth and Barris from the Lower 

 Carboniferous of Burlington and vicinity made prior to 1874, including numer- 

 ous types of species described by Meek and Worthen in the Illinois reports ; 

 of Walcott from the New York Trenton; of Dyer from the Cincinnatian ; and 

 of Schultze from the Eifel Devonian; — the Harvard material is of first impor- 

 tance in any investigation of the crinoids. 



At Yale University Museum there are important collections made by 

 Beecher in the New York "Devonian, containing types of species described by 

 Miss Talbot; and by Bradley and Hovey from the Crawfordsville beds of 

 Indiana, including types of some of my own species. 



