452 MARINE BIOLOGY OF THE SUDANESE RED SEA. 
the stout fringe in C. areolata. The merus is granular; it has a prominent 
rounded, somewhat upturned antero-external angle ; its anterior margin is 
notched, as also is its antero-internal angle, proximal to the latter notch is a 
smooth-floored depression. The ischium has a slight granulation anteriorly 
and slight pitting posteriorly ; it has a longitudinal groove to the inner side. 
of the middle line. 
Chelipeds subequal in length, a little less than twice the length of the: 
carapace, but one (left) chela is considerably the more massive. The whole 
surface of the chelipeds, including the larger rounded tubercles of the exposed 
surface of the wrist (2 tubercles mark the inner angle) and the tubercles of 
the upper border of the hand, is granulated. On the outer surface of the 
hand the tubercles become smaller, particularly on the lower part of the 
tuberculated area, and smooth, and tend to run in 4 longitudinal rows, of 
which the 3rd, counting from above, runs along the middle and is much the 
best defined, and the 4th runs on to the proximal portion of the fixed finger. 
The fingers are well arched, the apposed borders not meeting except at their 
cup-shaped tips, and each armed with three teeth. The arrangement of these 
teeth is the same in the two chele, but their relative proportions differ a good 
deal. In both chel those of the movable finger are equidistant, while the 
distal tooth of the fixed finger is well removed from the other two and faces | 
the large gap distal to the third tooth of the dactylus. In the smaller chela 
these teeth are of approximately equal size and not particularly large, but in 
the larger chela the Ist and 3rd of the dactylus and the 2nd of the fixed 
finger are enlarged. Hach dactylus has a few granules on its upper margin 
proximally, also a pitted groove on its upper margin, and both dactylus and 
fixed finger have two pitted grooves on the outer surface. 
Chelipeds in 2 (specimen 211) are little more than one-half as long again 
as the carapace. They are less massive than in the ¢, subequal and very 
similar. The fingers are less strongly arched than in the g, but, as in the g, 
they only meet at their hollowed tips. The teeth of the fingers are not 
enlarged except the middle one of the fixed finger, and this by no means to. 
the same extent as in the ¢. The armature is sharper, the granules of the 
tubercles of the wrist and upper border of the hand are crisp, the two tubercles. 
of the inner angle of the wrist are spiniform and curved, the smooth 
tubercles of the outer surface of the hand are conical and pointed ; on the 
same surface of the hand the tubercles extend almost to the ventral margin. 
Some of the above differences may be due to the smaller size of the 9 speci- 
men described as compared with the described ¢; it has, however, though 
non-ovigerous, the well-fringed broad abdomen, which may be taken to. 
indicate! sexual maturity. 
The dorsal margin of the walking-legs, the ventral margin of their last two 
joints, and to a jess extent the posterior surface of their et three joints bear: - 
