INTRODUCTORY \< >TE. 



Almost all that was saiil in the introductory note to the lirst |>art of tins work could truth- 

 fully lie said here. At that time it was thought that the 1'lumiilarida' was a uiiich larger family 

 than the Sertularida 1 . and the author has been greatly surprised at the laru'e number of -pecie- ni' 

 the latter family that he has lieeii called upon to discuss in the following pa<_jv-. and the extent 



to which the literature on the subject i- fragmentary and scattered will l>e ap]>arent when it is 

 said that not more than I'D species ( .f Sertnlarid;e from American waters have Keen mentioned 

 in any one publication up to the present time, while the present writer ha- found n le-> than 

 i:;n species that should he included in the American fauna. 



This lai'Ljv numlier of species has been brought to light more through a careful -crutiny of 

 foreign publications than through the discovery of new species in the large collections that have 

 passed through I he author's hands, although the number of the latter is by no means small, amount- 

 ing to more than :J'i new forms. The writer has thus been much impressed with the nece it\ of 

 bibliographic work, and, as a result, has presented as full a bibliography and as complete -\ non 

 y lilies of species as he has been able to secure. While this is true, it must be confessed that there 

 is much still to lie desired iii this direction, and that there are many papers that have not been 

 ayailable for reference, as will be seen b\ consulting the li-t on page 1 (:; of this work. 



This bibliographic work has been greatly facilitated by coiirte-ies from the authorities in 



charge of the Library of Congress in Washington, and by the courtesy of my colleague- at 1 e 



and abroad, who have been generous in sending me their publications. 



Almost all of the friends mentioned on page 1 of the lirst part of this \\ork have continued 

 to render aid in the preparation of the second part, and in addition I take plea-ure in expressing 

 my gratitude to the following: 



To the I )i rectors of the British Museum (Natural History) for portions of a number of Allman's 

 types of the ('/mil, mi, r Sertularida'; to Prof. (1. M. K. Levinsen, of Copenhagen, for .-pecimens. 

 literature, and advice; to Prof. I>'Aivy W. Thompson, of Dundee, for specimens and correspond- 

 ence; to 1 >r. ( leiiiens Ilartlaub for his valuable publications; to Prof. Maurice Bedot. of ( ieneva; 

 I>r. Kristine Bonnevie. of ( 'hristiania; l>r. Edward T. Browne, London, for literature: and Sir 

 William Dawson and Prof. .1. F. \Vhiteayes, of the ( 'anadian (ieological Suryey. for specimens. 



Among my own countrymen 1 have the pleasure to acknowledge aid from the following, in 

 addition to those mentioned in the acknowledgments on page L' of the lirst part of this work: 

 Hon. (ieorgeM. Mowers, for facilities granted for investigation at the laboratory of the I'. S. 

 Bureau of Fisheries, in Woods Hole, Massachusetts; to Prof. II. ( '. Bumpus for special favor- at 

 the same place; to Prof. William E. Hitter, of the Univer-ity of California, for -peeimen-; to 

 Prof. Trevor Kincaid. of the University of Washington, for specimens; to Mr.-, (i. (iibb- for 

 specimen.-, and to Dr. Harry Beal Torrey, of the University of California, for literature. 



The author also desires to acknowledge \\ith gratitude the great -er\ ice rendered by hi- 

 wife. and Prof. II. F. Wickliam of the State University of Iowa, in verifying reference- and other 

 bibliographic work connected with the preparation of thi- section of the monograph. 



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