MASKS AND FACES 53 
lateral margins of the carapace and the buccal frame. 
Milne-Edwards remarks that the grooves are often em- 
phasised about the middle of the carapace, so as to pro- 
duce the appearance of the capital letter H, the transverse 
Fie. 2.—Ethusa mascarone (Herbst). [Herbst] 
line being the upper boundary of the cardiac region. In 
some cases the grooves are so arranged as to represent 
very strikingly a human countenance or the caricature of 
one, as in the Masked Crab of Great Britain and the grimac- 
ing Hthusa mascarone of the Mediterranean, which is here 
shown as depicted by Herbst. Such likenesses the old 
writers were not at all disinclined to accentuate. 
The Brachyura are divided into tribes, in regard to 
which, however, there is not at present any absolute agree- 
ment among naturalists. We shall here arrange them 
under the names Cyclometopa, Catometopa, Oxyrrhyncha, 
Oxystomata, Anomala. It is melancholy, but scarcely 
avoidable, that an alternative list of names should have to 
be mentioned, for these tribes in the same succession may 
be called—-Cancroidea, Ocypodiidea, Maioidea, Leucosiidea, 
and Anomura apterura. The subjoined table will be use- 
ful for reference. 
