MONOGRAPH OF THE EXISTING CKINOIDS. 55 



Professor Bell in 1909 reported upon a collection of echinoderms made by the 

 Percy Sladen Trust expedition under the direction of Prof. J. Stanley Gardiner; 

 the species he records are: 



Actinometra multiradiata Comatella maculata. 



Antedon carinata ICosmiometra gardineri. 



Antedon palmata Stephanometra indica. 



Antedon spicata Cenometra emendatrix. 



In 1909, also, Professor Kcehler summarized, in a magnificent monograph, the 

 results of the researches of the Princesse- Alice; in this eight comatulids are included, 

 as follows: 



Antedon eschrichti Heliometra glacialis. 



Antedon lusitanica Thalassometra lusitanica. 



Antedon omissa, sp. nov Thalassometra omissa. 



Antedon phalangium. . \Leptometra celtica. 



[Leptometra phalangium. 

 Antedon prolixa Hathrometra prolixa. 



Antedon rosacea.. \ Antedon bifida. 



[Antedon mediterranea. 



Antedon tenella Hathrometra, sp. 



Eudiocrinus atlanticus Pentametrocrinus atlanticus. 



In 1910 Professor Koehler and M. C. Vaney published a preliminary note upon 

 the crinoids collected by the French steamers Travailleur and Talisman, and M. 

 Vaney described a new species of Promachocrinus (P. joubini) from the collections 

 of the Pourquoi Pas? under Dr. Jean Charcot. 



Beginning in 1907 the present author published a number of papers on the Cri- 

 noidea, describing new forms, suggesting new interpretations for various morpho- 

 logical and anatomical structures, and developing an entirely new scheme of classi- 

 fication which it was believed would be more satisfactory than any of the schemes 

 previously employed. These papers are all preliminary and more or less incomplete 

 expositions of the matter presented in the present memoir, and it has, therefore, 

 not seemed necessary to review them in this connection; bxit an account of the 

 development by the author of each of the systematic units herein used, showing 

 the steps by which it has been brought into its present form, is included under each 

 of the systematic headings. 



A study of these preliminary papers shows numerous misconceptions of sys- 

 tematic and morphological affinities and errors of other kinds, especially among 

 the earlier ones. These were chiefly the result of lack of material and necessary 

 dependence upon insufficiently detailed descriptions and figures. It is easy for the 

 man who does nothing to avoid making errors; but activity of any- kind necessi- 

 tates occasional mistakes. No thorough revision or comprehensive work of any 

 kind was ever done without a similar historv, and the author feels confident that 

 his errors will be found to be no more numerous nor more serious than those of his 

 predecessors 



