MONTAGUA MARINA. 
59 
of the peduncle reaches beyond the extremity of the 
peduncle of the superior. The last joint is rather more 
than half the length of the preceding, and the flagellum 
is not longer than the last joint of the peduncle. The 
mandibles are long, narrow, and furnished with a minutely 
serrated cutting margin. It is also furnished with a mi- 
nute secondary moveable plate having a serrated edge. 
This plate we believe to be common to the genus, but is 
not figured in the preceding species, from the probable 
fact that it exists only upon one mandible, the other 
being without it, as shown by Mr. Westwood’s dis- 
sections, published by Professor Bell, to be the case 
in Stegocephalus ampullus , the typical genus of this 
subfamily — where it exists upon the left mandible only. 
The pair of foot-jaws have all the joints subequal, 
the sixth being slightly longer than any of the others. 
The first pair of legs are short and slender, having the 
fourth joint anteriorly produced into a considerable pro- 
cess beneath the fifth. The fifth, or wrist, is nearly as 
long as the sixth, or hand, which is of a long elliptical 
form, having the palm convex, not defined, but armed 
with a few cilia. The second pair of legs are much 
longer, larger, and more powerful than the first. They 
have the fourth and fifth joints very short, but both 
anteriorly and inferiorly produced to an angle. The 
hand is long; the upper margin forming an arched line 
continuous with that of the wrist ; the palm runs 
diagonally with the axis of the hand, nearly straight 
to its base beneath, where two small tubercles, armed 
with a single blunt spine, carrying a small subapical 
bristle, define its limits. Throughout its entire length 
the palm is furnished with a row of equidistant solitary 
cilia. The finger is as long as the palm, somewhat 
curved, and tapering to the point, which, when closed, 
