CRUSTACEA OF THE MERGUI ARCHIPELAGO. SY 
internal hiatus of the orbits, the inferior margin of which is not 
united with the upper margin; the basal joint is rather small, 
the second scarcely reaches the front, and the third joint occu- 
pies the orbital hiatus, though not filling it. As in Myomenippe, 
the flagellum of these antenne is rather short, being only as 
long as the breadth of the front. 
The cephalothorax is rather enlarged, the proportion of its 
length to its breadth (the distance of the penultimate antero- 
lateral teeth) being, as Heller rightly observes, as 43 to 63. 
The upper surface is slightly convex longitudinally, being rather 
declivous towards the front and towards the antero-lateral 
margins; the posterior half is rather flattened and much de- 
pressed. The interregional grooves are very shallow, and some 
of them are scarcely or not at all indicated; besides the usual 
median frontal furrow, shallow gastro-branchial and branchio- 
cardiac grooves are present, the latter being, however, very 
faintly marked in young individuals. The transverse groove 
(cervical suture), which in other species separates the gastric 
region from the cardiac, is wanting. On each side of the 
gastric region, a faintly marked, arcuate sutural line is found, 
the inner end of which terminates in the middle of the gastro- 
branchial groove ; whereas the postero-external end issues into a 
short impressed line, which proceeds obliquely inward and back- 
ward from the last antero-lateral tooth. The same grooves are 
found also in Myomenippe granulosa, A. M.-Edw., in which they 
are very deep ; they are, on the contrary, very shallow and often 
scarcely distinct in Menippe Rumphii, Fabr. In Myom. granu- 
losa the regions are very prominent and covered with granules, 
while in Men. Rumphii they are only partly indicated and smooth. 
Though the upper surface is smooth and glabrous, it is, however, 
punctate, especially on the antero-lateral portions and on the 
gastric region; the punctations are generally minute, but some 
larger ones are scattered over the hepatic region, on the proto- 
gastric lobes, and on the arcuate sutural line, which occurs on 
each side of the gastric region. 
The shghtly prominent front is rather narrow, the distance of 
the internal angles of the upper orbital margins measuring 
scarcely more than one fifth of the greatest width of the cephalo- 
thorax. The front presents four obtuse rounded lobes; the 
internal lobes are broad and rounded, and nearly twice as broad 
as the external, which are much smaller, much less prominent, 
