106 A HISTORY OF EECENT 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. 



AcJiceiis, 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, Achceus Cran- 

 chii, 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 European seas and the Western North-Atlantic. 

 Three of these species are found in British waters, namely, 

 Inaclius dorsettensis (Pennant), Inachus dorynchus, Leach, 

 and Inachus leptochirus, Leach. 



Leptopodia, Leach, 1815, has apparently but one species, 

 Lepjtopodia 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 

 Pactohts, with the species Factolus Boscii, founded on a 

 single female specimen in the British Museum from some 

 unknown locality. Fabricius, he says, seems to have 

 described it as tbe other sex of his Inachus Sagittarius. 

 Factolus has a body exactly like Leptopodia., 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- 



