CRUSTACEA. 291 
width, whereas the smaller hand is still narrower. The 
rather little convex upper surface of the hands bears no 
longitudinal elevated ridge. The outer border of the palm 
that is entire and not dentate, is nearly straight, but 
the outer border of the immobile finger is curved inward, 
somewhat more that of the larger than that of the smaller 
hand and the entire inner border of the palm is also 
straight. The fingers of the larger hand of the adult male 
measure a third of its whole length, but those of the 
smaller chela are but little shorter than the palm; in 
younger specimens the fingers are comparatively a little 
longer. The triangular dactylus of the larger chela is ar- 
med at its under surface near the finely granulated inner 
border, with an oblong smooth tubercle, that is not 
found on the dactylus of the smaller hand. The fingers 
of the larger chela are glabrous on their inner borders, 
but those of the smaller are densely hairy. In one spe- 
cimen, apparently also a male, the fingers of the larger 
chela resemble those of the smaller, being longer than 
in the other specimens, likewise hairy on their inner 
borders and presenting no oblong tubercle: I consider it 
to be a variety. For the rest the anterior legs are gla- 
brous. The upper surface of the wrist is marked with fine 
oblique granulated lines, and appears finely granulated to- 
wards the anterior margin; the upper surface of the hands 
is also finely granulated, the granules being, however, 
not piliferous, but quite glabrous. The under surface of 
the hands is also minutely granulated near the inner border. 
The ambulatory legs resemble those of Petrol. inermis 
Heller. The meropodites of the first and second pair 
are armed on their anterior border with a single 
sharp spinule, the distance of which from the distal 
end of the border measures a fourth or a fifth of it, but 
those of the third pair i.e. of the penultimate pair of 
legs, are quite unarmed. The posterior border of the me- 
ropodites of the third pair of ambulatory legs is also en- 
tire, not dentate, but that of the meropodites of the 
Notes from the Leyden Museum, Vol. XV. 
