PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 45 
broad as the length, excluding the rostrum, but is rapidly narrowed ante- 
riorly, and at the bases of the antennz is scarcely half as broad. Back 
of the cervical suture the dorsal surface is regularly convex transversely, 
but the anterior part of the elevated gastric region is flat or slightly con- 
cave, and the orbital margins are perpendicular and hidden from above 
by the bases of the supraorbital spines. The anterior edge of the front 
is slightly arcuate and armed with five slender, acute, and subeylindri- 
cal spines, a median with two supraorbital each side; the median, or 
rostrum proper, is about half as long as the rest of the carapax, straight 
and horizontal; the supraorbital spines each side are approximately 
parallel with the rostrum, but directed slightly upward so that their 
tips are a little above the plane of the rostrum, are separated from the 
rostrum more widely than from each other, and the inner is nearly 
three-fourths as long as the rostrum while the outer is scarcely half as 
long as the inner. Immediately back of the outer of these spines there 
is a prominent and acute spine directed forward, and on a line between 
this and the hepatic spine of the lateral margin there are two much 
smaller spines on the steep side of the gastric region back of the orbit. 
The lateral margin is arcuate in outline and armed with seven acute 
spiniform teeth directed forward and decreasing successively in size 
posteriorly; the anterior, or antennal, is separated from the base of the 
antenna by a considerable space and is nearly as long as the outer 
supraorbital spine, the second is on the hepatic region, and the remain- 
ing five are all on the branchial region, the posterior one being very 
small in adult specimens and nearly or quite obsolete in young speci- 
mens 15™™ in length. The dorsal surface is marked with transverse 
Tug, is sparsely clothed with minute hairs, and, except the spines 
already mentioned, is unarmed. The cervical suture is well marked 
and the gastro-hepatic distinct. The infero-lateral region is of nearly 
the same form as in the typical species of Munida and terminates ante- 
riorly in an acute spine a little in front of the first lateral spine. 
The eyes are black, smaller than in the typical species of Munida, 
nearly globular, and are borne on short stalks, the whole length being 
scarcely more than a fourth greater than the diameter of the cornea. 
The peduncle of the antennula reaches to about the tip of the ros- 
trum; the segments are all approximately equal in length, nearly naked, 
entirely unarmed, slender, and subcylindrical, though the proximal seg- 
ment is cousiderably stouter than the others, and has a conspicuous 
protuberance over the auditory organ. The upper flagellum is about 
as long as thedistal segment of the peduncle, swollen toward the base, 
and tapered to a very slender tip. The lower flagellum is very slender 
throughout and shorter than the upper. The peduncle of the antenna 
reaches to about the tip of the second segment of the peduncle of the 
antennula, and is armed with numerous spines; the first segment is ex- 
posed at the antero-lateral angle of the carapax and projects anteriorly 
in a sharp tooth; the second segment is very short, armed externally 
