238 
THE VOYAGE OF H.M.S. CHALLENGER. 
distinct, the antero-lateral angles moderately prominent. The front (as in Macrophthal- 
mus and Gelasimus ) is very narrow and deflexed ; the orbits are very large and open, 
and extend along the whole anterior face of the body, between the front and antero- 
lateral angles (which are not very prominent), and their inferior margins are usually 
divided by a hiatus or fissure. The ridges of the endostome are usually not developed. 
The post-abdomen in the male is narrow and distinctly seven-jointed, with the terminal 
segment small and triangulate. The eye-peduncles are very large, and are jointed near 
the base, the basal part is short, and the terminal portion is often prolonged at its 
distal extremity as a spine or tubercle ; the come*, which are of great size, cover a great 
part of the inferior surface of the mobile portion of the eye-peduncles. The antennules 
are partially concealed by the front ; the antennae are very small, and are placed beneath 
the eye-peduncles in the narrow hiatus between the bases of the antennules and the 
interior subocular lobe of the orbit ; their basal joints are very short, and the flagella 
scarcely exceed the peduncles in length. The exterior maxillipedes are closely applied to 
the buccal cavity; the ischium-joints are longer than the merus-joints, and are distally 
truncated; the merus-joints are longer than broad, distally truncated, not emarginated at 
the antero-internal angles, and the next joint is articulated at the antero-external angle 
of the merus. The chelipedes in the adult male are unequal and well developed; the 
merus-joint in the larger chelipede is trigonous, with the superior and inferior margins 
denticulated; carpus short, with usually a lobe or tooth on the inner margin; hand 
vertically deep and compressed, the palm with a stridulating ridge on its inner surface 
(except in Ocypoda cordimana), composed of a vertical series of short raised lines 
or tubercles; fingers either distally acute or truncated, and denticulated on the inner 
margins. The ambulatory legs are somewhat elongated, with the joints usually granu- 
lated and the dactyli styliform. 
The species are found on the shores of nearly all the warmer temperate and tropical 
regions of the globe. 
Ocypoda ceratophthalma, (Pallas). 
Cancer ceratophtlialmus, Pallas, Spicilegia Zoologica, p. 83, pi. v. figs. 7-8, 1772. 
Ocypoda ceratophthalma, Fabricius, Entom. Syst. Suppl., p. 347, 1798. 
„ „ Milne Edwards, Hist. Nat. Crust., vol. ii. p. 48, 1834; Crust, in 
Cuvier, Regne Anim., ed. 3, Atlas, pi. xvii. fig. 1. 
„ „ Kingsley, Proc. Acad. Nat. Sci. Phil ad., p. 179, 1880, and references 
to synonyma, except Ocypoda eegyptiaca. 
„ „ .Miers, Ann. and Mag. Nat. Hist., ser. 5, vol. x. p. 379, pi. xvii. fig. 1, 
1882. 
North Australia, Raine Island, August 1874 (an adult male); Fiji Islands, Kandavu 
(a series of specimens, male, female, and young). 
