REPORT ON THE BRACHYURA. 
vii 
it, in several ways, however, brings into greater prominence true natural affinities 
existing between the different groups ; as, e.cj., in the approximation of the Oxyrhyncha 
to the Oxy stomata, and perhaps in the definite separation of the Leucosiidse from the 
latter group, nor can it be denied that the Dromiidse, at least, are so nearly related to the 
Brachyura that they may with almost equal justice be arranged with them or with the 
Anomura. Perhaps, therefore, this classification will upon further study be adopted by 
systematists in preference to the older one, which is followed in the present Report. 
The classification proposed in 1861 by Dr. Strahl, 1 who, basing his system upon the 
modifications of the structure and the position of the exterior antennae and especially of 
the basal joint, proposed four entirely new subdivisions of the Brachyura designated (l) 
Orbata, (2) Liberata, (3) Incuneata, and (4) Perfusa, needs no extended remark. The 
artificiality of his arrangement, and the inconvenience resulting from the dismemberment 
of the long-established groups, was exposed shortly after by the late Dr. W. Stimpson, 2 
the well-known American carcinologist, and it is to be regretted that the minor 
subdivisions of the Brachyura indicated by this author in his Preliminary Synopsis 
of the Crustacea collected by the U.S. Exploring Expedition to the North Pacific 3 
were never fully recharacterised, and the classification never worked out in detail. 
This latter remark applies also to his memoir on the Crustacea dredged in the Florida 
Straits, 4 where such definitions as are given are brief and incomplete. 
Several of the families and subfamilies indicated, but not always properly defined, by 
Stimpson, are adopted in the present Report. 
Dr. Camil Heller in 1863 5 limited the Brachyura in the sense indicated by M. H. 
Milne Edwards and Dana, and retains the four great subdivisions, Oxyrhyncha, 
Cyclometopa, Catometopa, and Oxystomata. Dana’s family Eriphiidse is not sustained ; 
and the Corystoid genera Atelecyclus, Thia, and Corystes are classed with the Oxystomata 
as in H. Milne Edwards’ system. 
Professor C. Claus in his Zoologie 6 divides the Brachyura into five tribes : — 
(1) Notopocla (including not only the Dorippidse, but also the groups Porcellanidse, 
Lithodidse, and Dromiidse, which have been generally included in the Anomura) ; 
(2) the Oxystomata, including besides the groups referred to this tribe by Dana, the 
Anomurous family Raninidse ; (3) the Oxyrhyncha (Majacea) ; (4) the Cyclometopa 
(Arcuata) or Can cro idea ; and (5) the Catometopa. The three last groups are limited as 
by Professor Dana ; the Corystidse and the Thelphusidse are included in the 
Cyclometopa. 
1 Moncitsber. d. Ic.preuss. Akad. d. JViss. Berlin, pp. 713, 1004, 1862. 
2 Amer. Journ. Sci. and Arts, vol. xxxv. p. 139, 1863; Ann. and Mag. Nat. Hist., ser. 3, vol. xi. p. 233, 1S63. 
3 Prodromus descriptionis Animalium evertebratorum, &c., Proc. Acad. Nat. Sci. Philad., 1857, p. 216 ; 1858, 
pp. 31, 93, 159. 
4 Bull. Mus. Comp. Zodl., vol. ii. p. 109, 1870. 
f> Die Crustaceen des siidlichen Europa, Wien, 1863, 8vo. 
6 Grundzuge der Zoologie, 4ter Auflage, Bd. i. p. 632, 1880. 
