228 A HISTORY OF RECENT CRUSTACEA 
It has been ascertained by Sars that a curious form which 
Kroyer described under the name of Myto Gaimardii is 
one of the larval stages of this seven-keeled Sabinea. In 
1842 Kriyer also instituted the new genus Arqis, to re- 
ceive the Arctic Crangon lar, described by Owen in the 
‘Zoology of Captain Beechey’s Voyage.’ Some years later 
Brandt established for the same species the genus Nectu- 
crangon, meaning ‘the swimming shrimp,’ in allusion to 
the swimming properties of the very dilated fourth and 
fifth pairs of legs. But, however appropriate, the name 
must yield priority to Argis. 
Sclerocrangon, Sars, 1882, has a hard and thickly in- 
crusted integument, a rostrum expanded below into a 
hatchet shape, a very short finger to the second legs, and 
the pleopods with the inner branch much shorter than the 
outer. This genus has been established to receive the 
Cancer Boreas, described in 1774 by the arctic voyager, 
J. C. Phipps, afterwards Lord Mulgrave. To the same 
genus is referred another Arctic species, the Crangon sale- 
Lrosus of Owen, and with less certainty the Mediterranean 
Crangon cataphractus, Olivi. 
Pontccaris, Spence Bate, 1888, with two species from 
the south of New Guinea, has a multicarinate carapace, 
short chelate second legs, and a branchial formula nearly 
the same as that of Pontophilus. 
Rhynchocinétes, Milne-Edwards, 1837, derives its name 
from the circumstance that the very large lamellate ros- 
trum is articulated with the carapace. The species Rhyn- 
chocinetes typus, Milne-Edwards, is found on the coasts of 
New Zealand, Australia, and Chili. 
Legion 2.—Polycarpineu. 
The name signifies literally ‘many-wristed,’ and the 
distinguishing character of the legion is that in the 
slender second pair of trunk-legs the carpus, wrist, or fifth 
joint is multiarticulate, that is, subdivided into a greater 
or less number of minor joints. It includes four families, 
Nikidee, Alpheide, Hippolytidz, and Pandalide. 
