viii ECHINODERMS OF THE BRITISH ISLES 



of amateurs to this group of animals, Avhich may well compete 

 with shells and insects both in beauty and variety of forms, 

 though certainly not in number of species. The information 

 given as to the best ways of preserving the various forms may 

 also prove useful in this connection. 



Besides the diagnoses, brief notes on biology, development, 

 and distribution of the various species are added. It is especially 

 hoped that the descriptions and figures of the pelagic larvae Avill 

 prove useful, and make the identification of these larvae a 

 comparatively easy task. 



I beg to offer this work as homage to that great nation which 

 so splendidly opened up the field of science that to me is the 

 most fascinating of all — the biology of the deep sea. 



My special thanks are due first to Professor J. Stanley 

 Gardiner, Cambridge, to whom it is especially due that this 

 work was undertaken and carried through ; then to Dr. E.J. 

 Allen, Plymouth, who kindly undertook reading proof and cor- 

 recting the language; further, to Messrs. F. M. Davis, Lowestoft; 

 G. P. Farran, Dublin ; C. C. A. Monro, British Museum, London ; 

 Dr. J. Ritchie, Edinburgh ; and A. W. Stelfox, National Museum, 

 Dublin, for important help with material or literature. Likewise, 

 I beg to thank Miss E. Deichmann, Copenhagen ; Drs. Austin 

 H. Clark, Washington, D.C. ; Torsten Gislen, Uppsala ; James 

 Grieg, Bergen ; Hj . Ostergren, Gothenburg ; H. J. Orton, Ply- 

 mouth ; and Sv. Runnstrom, Bergen ; Professors H. L. Clark, 

 Cambridge, Mass. ; W. K. Fisher, Pacific Grove, California ; 

 R. Koehler, Lyons ; T. Odhner, Stockholm ; and J. Richard, 

 Monaco, for most valuable assistance. 



TH. MORTENSEN. 



Copenhagen, February 1927. 



