MR. E. J. MIEES ON THE IDOTEID^. 8 



naturelle des Crustaces ' is Mr. Harger's memoir on the Marine 

 Isopoda of New England and the adjacent waters*. 



Here will be fonnd not only a very full and, I believe, accu- 

 rate account of the pi'incipal structural characters of tlie group, 

 but also detailed descriptions, accompanied by excellent figures 

 in outline, of all the genera and species inliabiting the eastern 

 coast of the Northern United States, together with much new 

 information regarding their geographical distribution, and a most 

 useful bibliographical list of the principal works relating to the 

 literature of the subject. 



I regret that I have frequently been unable to adopt Mr. 

 Harger's nomenclature, since a comparative study of the IdoieidcB 

 from all parts of the globe has necessitated the union of several 

 of the genera and species described by hiui with other previously- 

 known types ; but my obligations to- his work will appear 

 throughout the present memoir, and to it I must refer the student 

 for further information on the structure of the buccal and sexual 

 organs, and other points in the history of such species as inhabit 

 the region of which it treats. 



In Mr. Harger's classification the IdoteidcB are associated with 

 the ArcturidcB. 



In the present revision forty-seven species (besides several 

 varieties) are enumerated, distributed into four genera. 



Much additional value has been given to this memoir by an act 

 of generous liberality on the part of Prof. Alph. Milne-Edwards, 

 who, hearing that I was engaged on a revision of the IdoteidcB, 

 immediately placed at my disposal for examination the rich col- 

 lection of species of this group belonging to the Museum d'His- 

 toire naturelle of Paris, containing the types of Prof H. Milne- 

 Edwards's descriptions in the ' Histoire naturelle des Crustaces ;' 

 also specimens of the Algerian species described by M. Lucas, 

 and others of which I had previously seen no specimens. Thus 

 I have not only been able to identify the specimens in the Mu- 

 seum collection by actual comparison with the French types, but 

 also to redescribe the latter with the additional detail rendered 

 necessary by the large increase in the number of genera and 

 species in this family. 



I am also indebted to the Eev. A. M. Norman (who kindly lent 

 me two important memoirs which otherwise I could not have 



* Eeport of the U.S. Fish and Fisheries Oommiesioner for 1878 (pt. vi. 1880). 



1* 



