CRUSTACEA OF THE MERGUI ARCHIPELAGO. 127 
culate, presenting four or five minute teeth. The third tooth is 
very small, and separated from the preceding by a minute notch. 
The structure of the inferior orbital margin of the male is 
very characteristic, and different from that of ML. quadratus. 
The inferior orbital margin presents in its middle a broad, 
though little prominent, slightly triangular lobe, which is 
directed somewhat downwards, its obtuse tip being found 
at the internal or median side; the upper surface of this lobe 
is slightly concave. Behind this lobe, the inferior margin of 
the orbits presents a second, also obtuse, much smaller lobule, 
which is found at the external end of the under margin; whereas 
the internal or median part of the under margin, lying 
between the larger middle lobe and the epistome, is armed with 
a row of seven or eight minute rounded granules, the external 
one of which is the largest, whereas the others successively 
decrease in size towards the epistome, 7. e. towards the inner end 
of the orbital margin. 
The inferior orbital margin of the male JZ. quadratus, on the 
contrary, presents three prominent rounded lobes. In the 
female the inferior orbital margin is regularly and delicately 
erenulate, as in the female of MU. quadratus. The eye- 
peduncles are quite as long as the orbits. The somewhat 
hairy pterygostomian regions and the inflected sides of the 
cephalothorax present the ordinary structure seen in other species 
of this genus. The external foot-jaws have also the ordinary 
form. The sternum and the male abdomen are smooth and gla- 
brous, and sparsely and minutely punctate; all the joints of the 
male abdomen are distinct. The abdomen of the female occupies 
the under surface of the cephalothorax, lying between the legs, 
and its margins are fringed with hairs. 
The anterior legs of the male.are equal to one another in three 
specimens and unequal in the fourth; in their general appearance 
they resemble those of WM. guadratus. The anterior margin of 
the arm, which is a little dilated at the distal end, and the two 
other margins, are armed along their whole length with 
many small acute teeth. ‘T'he “musical crest” lies on the some- 
what hairy, upper surface close to the middle of the anterior 
margin and parallel to it. The outer and the under surfaces 
are also hairy. The wrist presents some acute granules at its 
internal angle; its upper surface is smooth. The hands are 
