PREFACE. 



More than foar years ago the writer formed a determination to pre 

 pare a monograph of the species of Dolphins which occur on the coasts 

 of Ii^orth America. It immediately became apparent, however, that a 

 proper comparison of the species described respectively by European 

 and American naturalists could not be made without an examination of 

 the types. A large proportion of the species of the family were estab- 

 lished by Gray, whose descriptions are for the most part too brief and 

 vague to serve as the basis of critical comparisons, while the descrij)- 

 tions of some other writers on the subject are almost equally insufiBcient. 



Such being the condition of the literature, I resolved to visit the 

 museums of Europe and to examine all the tyi)e specimens to which I 

 could gain access. Professor Baird, the late Director of the Museum, 

 very kindly consented to my being absent during the winter of 1883-'84, 

 and I accordingly spent about four months in England and on the con- 

 tinent of Europe in the study of the siiecimens in question. 



During this visit I became deeply indebted for courtesies shown me by 

 the authorities of the different museums. I wish especially to acknowl- 

 edge the kind attentions of Prof. William H. Flower, who not only 

 gave me free access to the collections of the Royal College of Surgeons, 

 which were at that time under his charge, but furnished me much valu- 

 able information, and, in addition, i^laced in my hands the proof-sheets 

 of his then unpublished paper on the Delpliinidce, to which I shall have 

 frequent occasion to refer in the following pages. Acknowledgment is 

 also especially due to Dr. Albert Giinther and Oldfield Thomas, esq., of 

 the British Museum; Prof. J. W. Clarke, of Cambridge, and Prof. H. 

 N. Moseley, of Oxford; Dr. George E. Dobson, of Netley; Thomas J. 

 Moore, esq., of the Liverpool Free Public Museum; Thomas Southwell, 

 esq., of the Norwich Museum; Prof. H. Paul Gervais and Prof Paul 

 Fischer, of the Museum d'Histoire Naturelle, Paris; Dr. F. A. Jentinck, 

 of the Leyden Museum ; and Prof. P. J. Van Beneden, of Louvain. 



In the course of my investigations I examined and measured the 

 majority of the types of Gray, Cuvier, Gervais, Schlegel, and other 

 English, French, and Dutch naturalists, together with numerous other 

 specimens. Basing my opinions on the results of this study, I shall 

 venture to pass in review the species of the different genera of the 

 family, giving little attention to the genera themselves. 



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