CRUSTACEA OF THE MERGUI ARCHIPELAGO. AL 
than the large rounded internal lobe of the infraorbital margin, 
which even extends a little more forward than the third frontal 
teeth, though less than the second. The external angle of the 
upper orbital margin is small and less prominent than the external 
angle of the under margin, from which it is separated by a small 
hiatus. The internal infraorbital lobe is united in this species 
with the obtuse internal angle of the upper margin, so that the 
orbits are perfectly closed internally, a character which even 
distinguishes the genus Myomenippe. This character is already 
present in the youngest specimen, which is only 22 millim. 
broad. According to Hilgendorf, the orbits of young spe- 
cimens of Myomenippe Fornasinii, 12 millim. broad, are also 
already closed internally, precisely as in the adult. The 
lateral margins of the cephalothorax are armed with four teeth, 
besides the small external orbital angle; these teeth are sepa- 
rated from one another by rather deep incisions, and their 
margins are minutely granulated. The first is triangular and 
acute, and its external margin is slightly emarginate. The 
second, the largest of all, is almost twice as long as the first, 
and its external margin is nearly straight. The third and 
fourth teeth are more acute than the two preceding; the third 
tooth is shorter than the second, but a little longer than the 
first, and it is directed straightly forwards, the external margins 
of both third teeth scarcely converging backwards. The fourth 
or last antero-lateral tooth is directed obliquely outwards and 
forwards. | 
The chelipedes of the male are a little unequal, the right 
being the larger in all these specimens. The arms project 
scarcely beyond the lateral margins of the cephalothorax. The 
upper margin of the arms terminates quite at the distal end 
in a small acute spine, which may easily be overlooked. The 
wrist presents an acute, prominent, dentiform, internal angle 
slightly curved upwards; the upper surface of the wrist is 
granular anteriorly outwards and along the inner margin, the 
granules being less distinct on the middle of the upper surface ; 
in the younger specimens the whole upper surface is more or 
less granular. In the adult male the length of the larger hand 
measures nearly three fourths of the breadth of the cephalo- 
thorax ; the hand is quite smooth on its outer and inner surfaces, 
and also on its under margin, but it is granular on and near the 
rounded upper margin, and some granules are also observed on 
