106 A HISTORY OF RECENT CRUSTACEA 
(Leach), is, like the preceding species, found both in 
British and Mediterranean waters, and is distinguished 
from the other species partly by the relatively greater 
length of the rostrum. 
Acheus, Leach, 1815, is so near to Macropodia that ‘it 
is in fact only distinguished from it by the absence of 
rostral spines; the rostrum in Achceus being composed 
merely of two small acute or subacute lobes.’ Of ten 
species enumerated by Miers only the type, Acheus Cran- 
chit, Leach, belongs to the waters of Europe and Great 
Britain. 
Indchus, Fabricius, 1798, as at present restricted, con- 
tained in 1886 only six species, and these known only 
from Huropean seas and the Western North-Atlantic. 
Three of these species are found in British waters, namely, 
Inachus dorsettensis (Pennant), Inachus dorynchus, Leach, 
and Inachus leptochirus, Leach. 
Leptopodia, Leach, 1815, has apparently but one species, 
Leptopodia sagittaria (Fabricius), with an extensive range 
in the warm waters of the Atlantic and of the West coast 
of America. Unlike the three preceding genera this has 
the rostrum not bifid, but simple. This beak is very 
long and serrate on the edges. The carapace is not 
spinous. The chelipeds in the male are rather slender 
and very elongate; the walking legs are very slender 
and extremely elongated, with the seventh joint stiliform. 
Next to this genus Leach placed one which he named 
Pactélus, with the species Pactolus Boscii, founded on a 
single female specimen in the British Museum from some 
unknown locality. Fabricius, he says, seems to have 
described it. as the other sex of his Inachus sagittarius. 
Pactolus has a body exactly like Leptopodiu, but the legs 
are of moderate length, and of these the first three pairs 
have simple claws, while the last two pairs are didactyle, 
that is to say, chelate. In 1793 Fabricius said of his 
sagittarius that in one sex the feet were of moderate size 
and all chelate, in the other six times as long and simple. 
In 1798, without any distinction of sexes, he states that 
eight of the feet are unguiculate and the last four pre- 
