CRUSTACEA OF THE MERGUI ARCHIPELAGO. 85 
rather obtuse. In specimens which are twice as large and 
22 millim. broad, the frontal teeth still fully resemble those of 
the youngest specimen. In larger individuals the frontal teeth 
appear gradually less rounded, more triangular, and pointed, 
and separated from one another by larger and deeper fissures, 
though the two median teeth are changing their form a little 
more slowly than the others, appearing obtuse, whereas tie 
other teeth are already pointed and acute. In a specimen 
50 millim. broad the two median teeth are blunt, the second teeth 
triangular, though still obtuse; the third and the fourth teeth, 
however, are very acute, especially the third. In the largest 
specimen in the Collection, which is 63 millim. broad, all the 
frontal teeth are sharp and acute, those of the first pair being 
even triangular and a little pointed. The frontal teeth are 
flattened and depressed, and the median teeth are slightly 
more prominent than the others. The front appears to me 
to be a little more prominent than in G. spiniferum ; but as the 
figure of that species is a double enlargement made from a 
young and small specimen, the drawing is perhaps somewhat 
inexact. 
The orbits are of the usual size, and their upper margin presents 
two narrow linear fissures ; the internal lobe of the inferior margin 
of the orbits is triangular and acute, and projects scarcely as 
much forwards as the internal angle of the upper margin. 
The inferior orbital margin is also marked with a fissure or 
hiatus. 
The antero-lateral margins are armed with six acute teeth, in- 
cluding the external orbital angles; the tips of all the teeth are 
dark-coloured. The first two teeth are of equal size; the third 
is a little larger, as in G. annulatum, Fabr.; the fourth is a 
little smaller than the third; the fifth is a little smaller than the 
fourth; and the sixth or last tooth is distinctly longer than the 
preceding, being directed transversely outwards and slightly for- 
wards*. Inthe younger specimens the last antero-lateral tooth is 
almost twice as long as the fifth, while in the largest specimen it 
* Though the first two antero-lateral teeth are slightly smaller than the 
third in this species, asin G. annulatum, Fabr., G. luciferum, Fabr., and G. japo- 
nicum, de Haan, they are, however, about as large as the fifth; in G. orientale, 
Dana=dubium, Hoffm., and in G. acutifrons, de Man, on the contrary, the 
second antero-lateral tooth is rudimentary, being in the last-mentioned species 
even scarcely perceptible. 
