Report on the zoological collections made in the Indo-Pacific Ocean ...

CEUSTACEA. 277slender penultimate joint of the first to third ambulatory legs ; theshort, curved dactyli are armed on their lower margins with a strongaccessory claw, posterior to which are one or two more small teeth.Colour (in spirit) yellowish. Length of carapace about 2| lines(5| millim.), breadth nearly 2 lines (4 millim.).This species is scarcely distinguished from the typical Porcellanalatifrons, Stimpson, except bj" the somewhat different deutieulation ofthe lobes of the front, and in the latter having, as it would seem, theposterior margin of the wrist armed, as well as the anterior, with threespines. The specimens described by Stimpson were from Hong Kong.Porcellana armata, Dana, has a much less prominent front.Porcellana streptocliiras of White*, from the Philippines, is, Ithink, a mere variety of this species.broader carapace, in having the frontal lobes armed with more numerousspinules, and in having the under surface of the merus of theIt differs only in the somewhatchelipedes armed with three or four spines in place of the singlespine in P. quadrilobata ; and these characters are possibly duo tothe greater age of the specimens.In one of AYhite's specimens the wrist is tridentate, in the other itissubentire.This species, in its elongated carapace and slender chelipedes,establishes a transition to the genus (or subgenus) Porcellanella, thespecies of which have a prominent and tridentate front. The generaof the Porccllanidca stand much in need of revision ; and I may addthat I doubt the constancy of the characters derived by Stimpsonfrom the size and number of the dcnticulations of the dactyli of theambulatory legs as generic distinctions.There are in the collection three small specimens from ThursdayIsland, 4-5 fms. (No. 165), which in many of their characters areclosely allied to P. serratifrons, Stimpson, yet are probably distinct,but to which, on account of their very imperfect condition, I willnot apply a specific designation. In one specimen the chelipede ispi'obably aborted, having the palm narrow and twisted and thefingers abnormally developed. These specimens are further distinguishedfj'om P. serratifrons by having three (not 1 or 2) spinules onthe 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 thelower margins of both right and left palms are spinulose.21. Galathea australiensis, Stimpson. (Plate XXXI. fig. A.)Here are referred a male from Port Denison, 4 fms. (No. Ill),and another from Port Molle, 14 fms. (No. 93), in the first collection;also a series of seven sj^ecimens from theArafuraSea, 32-36 fms.(No. 160), in the second collection, among which are both males andfemales. Stimpson's description was from a female. In the adultmales I have examined the palms are broader and the fingers havebetween them a hiatus when closed, and are strongly toothed on their* List Crust. Brit. Mus. p. Gl (1847), descript. nulla.