THE GEAPSOID CRABS OF AMERICA. 3 



United States collection of crabs. Not only was a series of photo- 

 graphs obtained, but arrangements were made for an exchange of 

 specimens whereby many cotypes and specimens directly compared 

 with types were secured for this museum. 



ACKNOWLEDGMENTS. 



My thanks are due to all those who assisted me during this Euro- 

 pean trip to Prof. E. L. Bouvier, Dr. F. Meinert, Dr. H. J. Han- 

 sen, Dr. K. Brandt, Prof. F. Jeffrey Bell, and Dr. R. I. Pocock; 

 and also to those who in the meantime have passed away Prof. A. 

 Milne Edwards, Dr. C. Liitken, Dr. F. Hilgendorf, and Prof. Henri 

 de Saussure. 



Were I to name all of the correspondents who have contributed 

 by advice, loans, gifts, notes, or otherwise toward the completion of 

 these volumes on American crabs, the list would include nearly all 

 carcinologists, museum curators, professors of zoology, and col- 

 lectors. 



At the moment, however, I am especially indebted to those who 

 have obtained for my use additional material in the Pinnotheridae, 

 a group difficult to understand without well-preserved and abundant 

 material. They are Dr. C. McLean Fraser, who recently collected 

 several hundred specimens in the neighborhood of Vancouver Island ; 

 Dr. F. W. Weymouth, who forwarded the collection belonging to 

 Stanford University ; Dr. Walter Faxon, who loaned the collection in 

 the Museum of Comparative Zoology ; and Dr. W. T. Caiman, of the 

 British Museum, who arranged the loan of a valuable type-specimen. 



Permission has been freely granted by Dr. H. M. Smith, Com- 

 missioner of Fisheries, and by Dr. C. H. Townsend, of the New York 

 Zoological Society, to use data which form part of special reports 

 as yet unpublished. 



The classification of the higher groups adopted in this report is 

 that of Borradaile, and the keys to the same have been borrowed 

 from his summary published in 1907. Likewise the definitions of 

 families and subfamilies are copied or adapted from those given by 

 Alcock in his work on the Catometopa of India. 1 



In the immediate preparation of this report I am indebted to my 

 colleagues in the United States National Museum, and above all to 

 Mr. Waldo L. Schmitt, assistant curator of marine invertebrates, 

 who has made most of the drawings of microscopic mounts of the 

 Pinnotheridae with the use of the Edinger drawing apparatus, and 

 has rendered important assistance in the preparation of manuscript 

 and plates. 



1 Materials for a Carclnological Fauna of India, No. 6. The Brachyura Catometopa 

 or Orapsoidea. Journ. Asiat. Soc. Bengal, vol. G9, Calcutta, 1900, pp. 279-456 [G21- 

 798]. 



