PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 43 
tally, and the ventral edge is armed with a slender spine at the distal 
end and a larger one a little way from the proximal end. 
The chelipeds are equal, and in the male about two and a half times 
as long as the carapax, and resemble those of M. Bamffia very closely. 
In the male, the merus is nearly as long as the carapax, the carpus 
about two-fifths as long as the merus, and the chela much longer than 
the merus, much more slender, with the digits fully three-fourths as long 
as the body, slender, straight, and the prehensile edges in contact 
throughout. Although the single male seen is very large, there is no 
sign whatever of the expansion of the chela at the base of the digits, 
due largely to a curvature in the basal part of the propodal digit, 
which seems to be characteristic of the old males of all the species of 
the genus. 
The dorsal surface of the abdomen is sculptured very much like the 
carapax, and the second and third somites are each armed with a series of 
small spines along the anterior edge above the facet, but there are no 
similar spines on the succeeding somites. The epimera of the second to 
the sixth somite are short, and obtusely rounded below, but those of the 
second and fifth are broader than the others. The telson and uropods 
are as in IM. Bamfia. 
As in all the other species of the genus which I have seen, the append- 
ages of the first abdominal semite are shorter than those of the second, 
and composed of a slender protopod and a single thin lamella, which 
is much shorter than the protopod, broad, obtuse at the distal extremity, 
with a few marginal set, and rolled together anteriorly into a spoon- 
shaped appendage; while the protopod in the second pair of appendages 
is much longer than in the first, and bears a narrow, setigerous, and 
somewhat twisted lamella, with a minute rudiment of a second lamella 
at its base. The appendages of the third, fourth, and fifth somites 
are alike, and in each the protopod (apparently) is expanded into a 
broad oval lamella, margined with long sets along the outer edge and 
at the tip, and bearing, on the inside near the tip, a small styliform 
appendage, composed of two segments. In the female the appendages 
of the second somite, though apparently not ovigerous, are about half 
as long as those of the third, with the protopod about as long as the 
endopod, which is composed of two subequal segments, and all the 
segments bear numerous long plumose set; the appendages of the 
third, fourth, and fifth somites are ovigerous, alike, nearly equal in size, 
and the two distal segments are subequal in length, and each about 
as long as the protopod. 
