CRUSTACEA OF THE MERGUI ARCHIPELAGO. 57 
of its breadth (2. e. the distance between the fourth antero-lateral 
teeth) to the length being as 124 to 9. As regards the structure 
of the upper surface of the cephalothorax, this species nearly 
completely agrees with H. indica, the anterior half presenting the 
same minutely granulated transverse elevated lines, in the same 
number, and arranged in the same manner; the inter-regional 
grooves, however, are a little more distinct, and the metabranchial 
regions, which are situated on each side of the cardiac region, are 
_ minutely granular. In the form of the front and in their orbits, 
both species closely resemble each other, so that one description 
suffices for both; but the anterior margin of the frontal lobes 
in this species is widely and more faintly emarginate, so that the 
external angles are much less prominent and not dentiform 
as in H. indica. The antero-lateral margins are comparatively 
much shorter than those of H. indica, so that a transverse line, 
uniting the fourth antero-lateral teeth divides the upper surface 
into two portions of very different length, the length of the 
anterior portion being in proportion to that of the posterior 
as 1 to 2. The antero-lateral margins are divided into four 
prominent teeth, including the external orbital angles. The 
first or anterior tooth is rather small, and much resembles the 
first antero-lateral tooth of H. cndica, the external margin being 
slightly emarginate. The second tooth is a little broader than 
the first, more prominent and rather obtuse; the third is the 
smallest of all, triangular, and much less prominent than the 
second and the fourth. The last tooth is conical and prominent, 
granulated above and moderately acute. The margins of the 
teeth are almost smooth. The inflected sides of the cephalo- 
thorax are nearly smooth, and only a little granular near the 
antero-lateral teeth; they do not present the tubercular eminence 
or tooth which is so characteristic of HZ. serratifrons and H. aus- 
traliensis. 
The outer antenne, the smooth epistome, and the anterior 
margin of the buccal cavity fully agree with H. indica. As 
in the latter, the endostome is distinctly ridged on each side. 
The external maxillipeds closely resemble those of H. indica; 
Stimpson’s words, “ Hectognathopoda sat hiantia,”’ are therefore 
inexplicable to me, seeing that the external maxillipeds of the 
species of Heteropanope perfectly resemble those of Pilumnus. 
The male abdomen is similar to that of H. indica, but the terminal 
joint is comparatively a little longer. The sternum and abdomen 
