XIV BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



this final part of the monograph it is rarely necessary to distinguish one arm from another 

 and the second usage is the one commonly found. Mr. Clark freely interchanges 

 anterior and distal and posterior and proximal in descriptions of the division series and 

 brachials. As for the centrodorsal, paiticularly in describing the more elaborate forms 

 found in the Zenometrinae and the Atelecrinidae, he has used besides proximal and 

 distal also upper, lower, basal, dorsal, and ventral as well as the usual apical and periph- 

 eral, which refer more to the cirri and cirrus sockets. Hartlaub also used proximal and 

 distal but John favored dorsal and ventral, which are clear enough as long as it is re- 

 membered that dorsal is downwards. I have tried to eliminate most terms other than 

 peripheral and apical and, where necessary, proximal and distal, but for the sake of 

 comparison I have given above a figure illustrating the orientation of many of these 

 terms, to supplement the glossary given in part 1. 



As for volume 2 of this work, dealing with the stalked crinoids, it appears that 

 Mr. Clark had made only isolated notes and references for it, so that a comprehensive 

 study of this small but interesting group will not be forthcoming from this source. 



After completion of the typescript, it was decided that this part of the mono- 

 graph should stand under the joint authorship of Mr. Austin Clark and myself. 

 References in the text to "the author" or "I" relate to Mr. Clark unless prefaced by 

 the initials "A. M. C." 



In addition to the acknowledgments and thanks expressed in the introductions to 

 the earlier parts of the monograph, I would like to extend my thanks particularly to 

 Dr. F. Jensenius Madsen of the Zoological Museum, Copenhagen, and to Elizabeth 

 Pope of the Australian Museum, Sydney, for so readily supplying information about 

 comatulids in the collections of their respective museums. 



Finally I would like to take this opportunity of saying how much pleasure and in- 

 struction I derived from working alongside Mr. Clark, though not on crinoids, for several 

 months in 1953 (for the award of a grant that made this possible, I am indebted to the 

 International Federation of University Women) . The completion of this monograph 

 stands as a memorial to Mr. Clark. 



AILSA McGowN CLARK. 

 British Museum (Natural History) 

 June 1960 



