IV 
THE VOYAGE OF H.M.S. CHALLENGER. 
SYSTEMATIC CLASSIFICATION OF THE BRACHYURA. 
v 
In place of a complete bibliographic al list I subjoin the following brief notice of the 
classifications proposed by the leading systematists. If time and opportunity had 
permitted, even this short abstract of the subject could have been with advantage treated 
in greater detail and thereby rendered more complete. 1 
Professor H. Milne Edwards, in 1834, in the first volume of his great work, 2 separated 
from the Brachyura of earlier authors, and designated Anomura, those forms in which 
the sternum is linear, and the post-abdomen is less closely inflexed beneath the sternal 
surface of the body, and bears more or less well-developed appendages upon the pen- 
ultimate segment. He divided the restricted Brachyura into the four great natural 
groups or subdivisions, Oxyrhinques (Oxyrhyncha), Cyclometopes (Cyclometopa), 
Catometopes (Catometopa), and Oxystomes (Oxystomata), which have been retained by 
most succeeding authors, and are adopted in the present Report, with these modifications 
only, that I follow Professor Dana in placing the Thelphusinea (which are regarded by 
Milne Edwards as a tribe of the Catometopa) and the somewhat heterogeneous group 
Corystoidea in the Cyclometopa ; the affinities of the Corystoidea, however restricted, 
seeming to be rather with the Oxyrhyncha and the Cyclometopa than with the 
Oxystomata where Milne Edwards places them. 
This method of restricting the Brachyura, indicated in the Histoire naturelle des 
Crustaces, was apparently adhered to by Milne Edwards in 1852 in the article entitled 
<£ Observations sur les affinites zoologiques et la classification naturelle des Crustaces,” 3 
where, however, the term Ocypodidae is adopted for the group designated Catometopa in 
his earlier work, and an arrangement of the genera proposed, which I think to be in many 
particulars less natural and convenient to systematists than that of Dana, which appeared 
almost contemporaneously, and which in its turn has been modified by Dr. Stimpson and 
in the present Report.- 
It will be unnecessary to refer in further detail to the arrangement of the families 
and subfamilies indicated in the Histoire naturelle des Crustaces, a work which is in the 
hands of every student of the group. 
De Haan, in 1835-1849, in his great work on the Crustacea of Japan, 4 which is a 
standard -work of reference with all students of the Crustacea, divides the Brachyura into 
two great primary sections or groups, as follows: — (1) Brachygnatha, with the four 
subdivisions Cancroidea, Majacea, Dromiacea, and Trichidea, and (2) Oxystomata, 
1 Reference is made here only to those works which deal in a general way with the arrangement of the whole group, 
and not to several papers where special families or subfamilies are dealt with, nor, of course, to many memoirs relating 
to the faunae of particular regions, or describing collections from special localities. 
2 Hist. Nat. des Crust., vol. i. pp. 247, 263, 1834. 3 Ann. d. Sci. Nat., ser. 3 (Zool.), xviii. p. 126, 1852. 
4 Crust, in v. Siebold, Fauna Japonica, Introd., p. xi., 1849. 
