REPORT ON THE BRACHYURA. 
221 
female); Kandavu, Fiji Islands (an adult female); Tahiti, September 30, 1875 (two adult 
males and two females); Papiete (Tahiti), September and October, 1875 (three adult 
males and an adult female). 
An adult male from Tracey Island measures as follows : — 
Adult g. 
Lines. 
Millims. 
Length, of carapace, about 
31* 
67 
Breadth of carapace, about 
40 
85 
The Challenger examples fall into two very distinct series which may thus be 
characterised :• — In the first, to which belong the specimens from Tahiti, the carapace is 
moderately tumid at the branchial regions ; the postfrontal and postorbital prominences 
of its dorsal surface are not very prominent ; the exterior orbital tooth is prominent, 
although small, and is followed rather closely by the epibranchial tooth ; the antero- 
lateral margins are defined by a very distinct raised line, which extends halfway along 
the postero-lateral margins, and the exterior subocular angle of the carapace is about a 
right angle. These are apparently the form distinguished by M. cle Man as the typical 
Cardiosomci ccirnifex. In the second form, to which belong the specimens from the 
Admiralty Islands and Kandavu, the carapace is much more swollen and arched at the 
branchial regions, the postfrontal and postorbital prominences are much more prominent, 
the exterior orbital tooth less prominent, the lateral epibranchial tooth more remote from 
that at the outer angle of the orbit ; the raised line defining the antero -lateral margins 
of the carapace is shorter, and the exterior subocular angle more acute. I may add that 
the merus of the exterior maxillipecles generally narrows more decidedly to its base in the 
typical Cardiosomci carnifex. 
This form may, I think, be identified with Cardiosomci hirtipes of de Man (tom. cit., 
p. 34), though perhaps not of Dana, but the basal antennal joint is usually somewhat 
excavated, and the clielipedes in the male are often unequally developed. 
Family II. Ocypodidj. 
Ocypodiens , Milne Edwards, Hist. Nat. Crust., vol. ii. p. 39, 1837. 
Macroplitlialmidx (pt.), Dana, U.S. Explor. Exped., vol. xiii., Crust. 1, pp. 308, 312, 1852. 
Ocypodiac.es e, Milne Edwards (pt.), Ann. d. Sci. Nat., ser. 3, Zool. xviii. p. 140, 1852. 
Carapace usually moderately convex, cancroid or trapezoidal, with the antero-lateral 
margins straight or arcuated, but the branchial regions not greatly dilated, as in the 
Geocarcinidse ; the front of moderate width, or very narrow. Orbits and eye-peduncles 
sometimes of moderate size, sometimes very greatly developed. The post-abdomen does 
not always cover the sternum at the base between the bases of the fifth ambulatory legs. 
The carpal joint of the endognath of the exterior maxillipedes is inserted at the antero- 
internal, or, rarely, at the antero-external angle of the merus. The chelipedes (in the 
