PREFACE 



The preceding parts of U.S. National Museum Bulletin 82, A Monograph of the 

 Existing Crinoids, volume 1, the Comatulids, by Austin Hobart Clark, have been 

 published as follows: 



Part 1, [General], vi+406 pp., figs. 1-513 in text and 514-002 on 17 pis., 



1915. 

 Part 2, [General], xxv+795 pp., figs. 1-949 in text and 950-13G4 on 57 pis., 



1921. 



Part 3, Superfamily Comasterida, vii+816 pp., 227 figs, on 82 pis., 1931. 

 Part 4a, Superfamily Mariametrida (except the family Colobometridae), 



vii+603 pp., 283 figs, on 61 pis., 1941. 

 Part 4b, Superfamily Mariametrida (concluded the family Colobometridae), 



and Superfamily Tropiometrida (except the families Thalasso- 



metridae and Charitometridae), vii+473 pp., 220 figs, on 43 pis., 



1947. 

 Part 4c, Superfamily Tropiometrida (the families Thalassometridae and 



Charitometridae), vii+383 pp., 104 figs, on 32 pis., 1950. 



For volume 2 of this work, dealing with the stalked crinoids, Austin H. Clark 

 left, upon his death on October 28, 1954, only isolated notes and references. Com- 

 pletion of this part of the monograph, therefore, must devolve upon a new generation 

 of students of these interesting animals. 



Completion of volume 1, part 5, was undertaken some years ago by Ailsa M. 

 Clark of the British Museum (Natural History), who patiently and expertly revised 

 and brought up to date (1960) Mr. Clark's original notes and manuscript, most of 

 which had been done in the early 1920's, and retyped the whole into a publishable 

 manuscript. This tedious task, gladly undertaken, is in the highest tradition of 

 service to science. For this service, the Smithsonian Institution and its Museum of 

 Natural History, and students everywhere, must acknowledge a deep indebtedness. 



RICHARD S. COWAN 



Director, Museum of Natural History, 



Smithsonian Institution 



