CRUSTACEA. 57 
first article, arise the antenne proper: three articles (second, third, and fourth of the series) 
follow one another within a distance of about half an inch, the first two being small and irreg- 
ular, the next is subtriangular or rather compressed ; to the latter is appended the remaining 
portion of these organs, composed of narrow and circular articles, increasing in length up to 
the middle of their extent, hence diminishing again gradually towards their filiform apex. 
The superior antennce, two inches and three quarters in total length, are composed of a basal, 
rather large and subtriangular piece, anteriorly tapering into several points, followed by two 
small articles, upon the latter of which, the smallest of the series, are inserted: first, a filiform, 
transversally and minutely articulated antenna; and, second, a flattened, much shorter an- 
tenna (about half an inch long), provided inferiorly or interiorly with a series of closely-set 
hairs or sete. 
The eyes, inserted upon a short peduncle immediately above the superior antenne, are large 
and conspicuous, and when inflexed they are lodged in a concavity of the basal article or seg- 
ment of the organs just alluded to. 
The rostrum, one inch and an eighth in total length, is very much compressed, and thin, 
tapering off towards its extremity, which is slightly curved downwards, and provided upon said 
curvature with ten acerated spines, directed forwards, the anterior one being the largest, and 
constituting the very extremity of that piece. Two more spines, similarly directed forwards, 
exist upon the upper margin, one near the base, the other a quarter of an inch anteriorly. The 
inferior edge is provided upon its whole extent with eighteen spines, similar to the anterior 
upper ones, but much larger and broader posteriorly. On the posterior edge of each of the 
latter spines exists a series of minute and closely-set hairs. 
The anterior—pincers-bearing leg—is the stoutest and longest of the five pairs; the second 
pair is the most slender and the shortest ; the third, fourth, and fifth pairs are equal as far as 
stoutness is concerned, but the third pair is a little longer than the fourth, and the fourth a 
little longer than the fifth pair, which is somewhat longer than the second, 
The first (basal) and second articles in the five pairs of legs are similar and proportional in 
their development; the first is an annular ring, bearing a rudimentary palpiform appendage, 
similar to that observed upon the basal article of the jaw-leg ; tle second is subtriangular and 
acute exteriorly. 
In the first pair of legs the third article is a little larger and more acute exteriorly than the 
second. The fourth article is long, compressed towards its base, and subcylindrical anteriorly, 
where it is provided with asmall spine. The fifth article is short, subprismatic, bearing a 
large spine upon its anterior margin, and several small ones beneath and exteriorly. The sixth, 
which forms the claw, is the stoutest and longest, bearing upon its extremity three small, black 
spines ; the upper piece of the claw is slightly arched, bearing upon its convexity a well-devel- 
oped tuft of hairs ; its anterior extremity is provided with a series of about a dozen small, black 
spines, largest near the apex. 
In the second pair of legs the third article is nearly as long as the fourth, and similar to the 
latter in shape, in a reverse position. The fifth article is the longest, and subcylindrical. The 
sixth article, which bears a small claw, is likewise subcylindrical, or slightly compressed and 
elongated. The moveable upper piece is provided anteriorly with four small, black spines, 
whilst there are but two below. 
In the third, fourth, and fifth pairs of legs the third article is a little larger than the second, 
and also more acute. The fourth article, the longest of all, is compressed, and provided along 
its external edge with three or four small spines. The fifth article, one-third shorter than the 
sixth, is likewise compressed, and provided externally with a few minute spines. The sixth 
is slender, a little shorter than the fourth, provided with exceedingly minute spines beneath, 
and terminated by a subconical and slightly-curved spine, moveable upon the latter, representing 
a seventh article. 
The caudal region, composed of six segments, is rather stout, compressed, higher than broad 
