vi THE VOYAGE OF H.M.S. CHALLENGER. 



regards the Anomura at least, a perfectly natural one. To him we are indebted for first 

 correctly noting the affinities of the Galatheidge, and since the publication of his work no 

 naturalist has questioned the propriety of including this group in the Anomura. 



As a result of his unrivalled opportunities of studying the Crustacea as a whole, 

 enjoyed while naturalist to the United States Exploring Expedition under Captain 

 Wilkes, Professor J. D, Dana paid special attention to the subject of classification, and the 

 result of his investigations has been given to the world in the most elaborate work which 

 has ever appeared on this group of animals.^ This eminent authority includes under the 

 term Anomoura those groups admitted by Milne-Edwards, with in addition the Gala- 

 theidae, and such doubtful forms as the Bellidea. Proceeding from the standpoint that 

 the Anomura are to be regarded as degraded forms, intermediate between the Brachyura 

 and the Macrura, he subdivides the group into the four following grades : — (1) Anomoura 

 superiora, including the Dromidea, Bellidea, and Eaninidea ; (2) Anomoura media, 

 including the Hippidea and the Porcellanidea ; (3) Anomoura submedia, including the 

 Lithodea ; and (4) Anomoura inferiora, including the Paguridea, and the Galathseidea. 

 At the same time he has indicated in each case the Brachyuran group of which he 

 considers the subtribes of Anomura as degraded forms. Dana's classification, though 

 subsequently adopted by many systematic WTiters, is admittedly cumbersome and 

 inconvenient in many respects, his sections appear unnecessary, and in constituting them 

 he has in several cases separated groups which are closely related. 



A few years subsequent to the publication of Dana's great work, another American 

 naturalist, Dr. William Stimpson, who had taken part in the exploring expedition to 

 the North Pacific, published a Preliminary Report on the Crustacea, which includes a 

 synopsis of all the species of Anomura known at that time.^ In this paper, the value of 

 which to any worker in the group can scarcely be over-estimated, he divides the Anomura 

 into two sections, according to the nature of the last thoracic segment, whether united to the 

 preceding, or free, and termed respectively Teleosomi and Schizosomi. The former includes 

 the Dromidea, LatreUlidea, Homolidea, and Eaninidea, and the latter the Porcellanidea, 

 Hippidea, Lithodidea, Paguridea, Aegleidea, and the Galatheidea. In the limitations of 

 the group he has followed Professor Dana. It is greatly to be regretted that Stimpson's 

 final Report has never been published. The Crustacea of the North Pacific Expedition 

 were destroyed in the great fire at Chicago, but the complete MS. of the final Report, as 

 far as the end of the Anomura, which it was at one time thought had perished, was 

 afterwards discovered along with figures of the new species among papers left by Stimpson 

 at the Smithsonian Institute. A special feature of this author's work is the large 



1 Crustacea, in United States Exploring Expedition, vols. xiii. and xiv., 1852. 



2 Prodromus descriptionis Animalinm evertebratorum quae in Expeditions ad Oceanum Pacificum Septemtrionalem 

 a Republica Federal! missa Cadevaladero RinggoH et Johanne Rogers ducibus observavit et descripsit Gulielmus 

 Stimpson, Proc. Acad. Nat. Sci. Philad., December 1858. 



