CRUSTACEA OF THE MERGUI ARCHIPELAGO. 55 
tubercular eminence, as in H. serratifrons, or a small tooth, as in 
HT. australiensis. The basal joint of the external antenne is 
short and small, and does not nearly reach the front; the other 
joints occupy the internal orbita] hiatus, and the flagellum is 
rather short, measuring only a fourth of the distance between 
the third antero-lateral teeth. The endostome is distinctly longi- 
tudinally ridged on each side. The epistome is nearly smooth. 
The male abdomen is seven-jointed, the joints being all distinctly 
separated from one another ; it closely resembles that of some 
Pilumni, and the penultimate joint is nearly quadrate, being 
scarcely broader than long. The sternum and the abdomen are 
smooth, though somewhat pubescent, and the lateral margins of 
the female abdomen are fringed with rather long hairs. 
The chelipedes are very unequal, the right being the largest 
in both specimens; although the larger chelipede of the female 
specimen is wanting, I suppose that the anterior legs pre- 
sent the same size both in the male and in the female. The 
arms are short, scarcely projecting laterally beyond the lateral 
margins of the cephalothorax; they are armed near the distal 
end of the upper margin with a strong, acute, somewhat curved 
tooth. The under margin is entire, but the anterior margin is 
somewhat granular and hairy. The external (or posterior) sur- 
face of the arm is minutely granular near the upper margin, but 
otherwise the arms appear smooth. ‘The wrist is armed with a 
small, scarcely acute tooth at the distal and internal angle; its 
upper surface appears smooth to the naked eye, but, when seen 
under a lens, some small granules are observed near the internal 
and external margins, especially on the wrist of the smaller 
chelipede. The larger hand is very large, its length (the fingers 
included) being but little shorter than the breadth of the 
cephalothorax, 7. e. the distance between the third antero-lateral 
teeth. The fingers are nearly half as long as the palm, which 
is but little longer than broad (high). The outer surface 
of the palm is rather convex and quite smooth, and the obtuse 
upper and under margins, like the inner surface, are also per- 
fectly smooth. The fingers have pointed tips, which cross one 
another; they are nearly smooth, the immobile finger pre- 
senting only a trace of a longitudinal impressed line on its 
outer and inner surfaces, and the mobile finger being slightly 
granular above at the articulation. The latter presents a some- 
what larger tooth at its base, and the other finger is armed with 
