• REPORT ON THE A NOMURA. vii 



number of new genera which he introduced into the Anomura, and most of these are, in 

 my opinion, founded on sufficient grounds. I have in the following Report figured 

 several of Stimpson's species which were retaken by the Challenger, and at the same 

 time have made additions to his original descriptions. 



Professor Alphonse Milne-Edwards, in the introduction to his History of the Fossil 

 Stalk-Eyed Crustacea,^ refers the Anomoures Apterures of his father to the Brachyura, 

 under the designation of " Brachyures Anormaux," while he places the Pterygures in the 

 Macrura, thus abolishing the Anomura as a distinct group. 



A somewhat similar plan has been adopted by Professor C. Claus," who places the 

 Galatheidse, Hippidse, and Paguridse in the Macrura, while he ranges the Porcellanidas, 

 Lithodidse, and Dromidse among the Brachyura in a family which he has designated 

 Notopoda. An arrangement which separates such forms as Porcellana and Galathea 

 cannot, however, be regarded as a natural one. 



The most recent and in some respects one of the most important contributions to the 

 subject is that of Dr. Boas.^ This writer, proceeding on somewhat similar lines to De 

 Haan, restores the Anomala of the latter author to its original position, constituting it a 

 distinct group, equivalent to such others as the Thalassinidse or Brachyura, rather than a 

 mere collection of heterogenous forms. He subdivides the Anomala into three branches, 

 the Paguroidge, Galatheidee, and Hippidas, while he divides the Brachyura into two 

 sections, viz., the Dromiacea, and the genuine Brachyura. There is much to be said in 

 favour of this view, and all carcinologists owe a debt of gratitude to Boas for his careful 

 work ; at the same time I cannot agree with him as to the propriety of reducing a number 

 of previously "constituted genera to the rank of subgenera. 



The group which was placed in my hands by the Challenger authorities constituted 

 the Anomura as defined by Dana. In the classification adopted in the Report I have 

 followed to a certain extent the arrangement of Boas, but as the Dromidea and Raninidea 

 appear to me groups of very doubtful position, I have retained them with some hesitation 

 and reluctance in the Anomura. 



1 have adopted the hitherto almost universally accepted term of Milne-Edwards, in 

 its more correctly spelt form Anomura. The Anomaux, as previously constituted by 

 Latreille, formed a group of quite different proportions, and the term Anomala is 

 therefore in my opinion not entitled to claims of priority. 



' Ann. d. Sci. Nat. (Zool.), ser. 4, t. xiv., 1860. 



2 Grundziige der Zoologie, 4ter Auflage, Bd. i., 1880. 



2 Studier over Decapodernes Slaegtskabsforhold af J. E. V. Boas, VansL Vidensk. Selak. Shift. (6te E.), Bd. i. 

 pp. 26-210, pis. i.-vii., 1880. 



