b PREFACE. 



the privilege of studying the collections of Crustacea in 

 the California Academy of Sciences. The examination 

 of Mr. Lockington's type specimens, many of which are 

 in the possession of the Academy, has made it possible 

 to straighten out some questions which otherwise would 

 scarcely have been capable of solution. To Mr. Rivers 

 and Mr. Harford, formerly of the University of Cali- 

 fornia, I am indebted for the privilege of studying the 

 collections in the University museum. From Miss Mary 

 J. Rathbun and Dr. James E. Benedict of the U. S. 

 National Museum much valuable aid has been received 

 which is gratefully acknowledged. 



S. J. HOLMES. 



UNIVERSITY OF MICHIGAN, 

 Ann Arbor, Mich. 

 January 20, 1900. 



