T r
he does not notice that the outer margin of the smaller chelipede
is armed with a scries of minnte spinules, which are often concealed
by the pubescence. The smaller chelipede in the adult male and
both chelipedes in the smaller specimens have the anterior margin
of the wrist armed with two teeth, and in the smaller specimens
(which yet I cannot think belong to a distinct species) the frontal
and upper orbital margins are very minutely spinulose. There is
developed in both chelipedes a more or less distinct longitudinal
median ridge on the upper surface of the wrist and palm, and the
outer margin of the hand in both is armed with a series of small
spinules, so th at these specimens in many points resemble Porcellana
ornata, Stimpson, from Hong Kong.
20. Porcellana quadrilobata. ( P l a t e XXX. fig. D.)
In the single male from Port Denison, 4 fms., thus designated, the
carapace is shaped nearly as in Porcellanella triloha, th at is, it is much
longer than broad, with the sides very slightly arcuated. The upper
surface, ivhen viewed under a lens of sufficient power, is seen to he
marked with numerous rather closely-set transverse striæ. The inter-
antennularj" portion of the front, which in P. triloha is entire, is in P.
quadrilobata divided by a median triangular notch (which, however,
is not so deep as the lateral notches), hence tho front appears 4-lobed.
The lobes arc triangular and acute ; on the inner margin of each of
the outer lobes is a small spinule, and the inner margins of each of
the inner lobes is minutely serrated. There is a very small tooth or
spine at the outer orbital angle, and posterior to this the sides of the
carapace are armed with five spines, tlie three posterior of which are
placed near to one another and separated by a somewhat wider interval
from the preceding tooth. On the inferior surface of the carapace,
below the inferior orbital margin, there is a strong spine. The
eyes are set on very short pedicels, and are nearly concealed within
the orbits. The joints of the peduncles of the antennæ are short (the
flagella wanting in the single specimen examined). There is a spine
at the distal end of the basus-joint of the outer maxillipedes ; the
ischium-joint is somewhat dilated, scarcely at all emarginate at its
distal end, where it is articulated with the merus, which is excavated
at its distal extremity ; the three following joints are moderately
robust. The chelipedes are proportionately rather slender and elongated
; the merus or arm is short, its inner margin somewhat cristiform,
and terminating in a thin suhacute lobe ; there is a spine also
on the under surface of the merus ; the wrist is about as long as the
palm, and is armed with three spines or teeth on its inner margin ;
the hand is slightly contorted ; the surface both of hand and wrist
finely striated ; the fingers are rather shorter than the palm, meet
along their inner edges when closed and cross at the tips, which are
incuiwed ; at the bases of the inner margins of the fingers is a patch
of hair ; the lower margin of tho lower finger is armed with aseries
of small spinules. The ambulatory legs are rather slender ; there are
a few short stiff setce, or mobile spines, at the distal end of the
slender penultimate joint of the first to third ambulatory legs ; the
short, curved dactyli are armed on their lower margins with a strong
accessory claw, posterior to which are one or two more small teeth.
Colour (in spirit) yellowish. Length of carapace about 2g lines
( 5 | millim.), breadth nearly 2 lines (4 millim.).
This species is scarcely distinguished from the typical Porcellana
latifrons, Stimpson, except by the somewhat different denticulation of
the lobes of the front, and in the latter having, as it would seem, the
posterior margin of the wrist armed, as well as the anterior, with three
spines. The specimens described by Stimpson were from Hong Kong.
Porcellana armata, Dana, has a much less prominent front.
Porcellana streptocliirus of White*, from the Philippines, is, I
think, a mere variety of this species. I t differs only in the somewhat
broader carapace, in having the frontal lobes armed with more numerous
spinules, and in having the under surface of the merus of the
chelipedes armed with three or four spines in place of the single
spine in P. quadrilobata ; and these characters are possibly due to
the greater age of the specimens.
In one of AA’hite’s specimens the wrist is tridentate, in the other it
is suhentire.
This species, in its elongated carapace and slender chelipedes,
establishes a transition to the genus (or suhgenus) Porcellanella, the
species of which have a prominent and tridentate front. The genera
of the Porcellanidea stand much in need of revision ; and I may add
th at I doubt the constancy of the characters derived by Stimpson
from the size and number of the dentieulations of the dactyli of the
ambulatory legs as generic distinctions.
There are in the collection three small specimens from Thursday
Island, 4 -5 fms. (Xo. 165), which in many of their characters are
closely allied to P. serratifrons, Stimpson, yet are probably distinct,
but to Avhich, on account of their very imperfect condition, I will
not apply a specific designation. In one specimen the chelipede is
probably aborted, having the palm narrow and twisted and the
fingers abnormally developed. These specimens are further distinguished
from P. serratifrons by having three (not 1 or 2) spinules^ on
the sides of the branchial regions, six to eight spines on the anterior,
and two on the posterior margin of the carpus of the chelipede, &c.
In the single specimen (a young one) possessing both chelipedes the
lower margins of both right and left palms are spinulose.
21. Galathea australiensis, Stimqjson. ( P l a t e XXXI. fig. A.)
Here are referred a male from Port Denison, 4 fms. (Xo. I l l ) ,
and another from Port Molle, 14 fms. (Xo. 93), in the first collection
; also a series of seven specimens from the ArafuraSea, 32-36 fms.
(No. 160), in the second collection, among which are both males and
females. Stimpson’s description was from a female. In the adult
males 1 have examined the palms are broader and the fingers have
between them a hiatus when closed, and are strongly toothed on their
* List Crust. Brit. Mus. p. 64 (1847), descript, nullâ.
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