66 A HISTORY OF RECENT CRUSTACEA 
the other hand, complaints are made by English writers of 
the mischief which it does to fish already captured, and 
Dr. Hoek accuses it of the truly detestable crime of in- 
vading the oyster beds, and eating the young oysters while 
their shells are still soft and easy to break. In attacking 
the adults, it 1s itself sometimes caught by the snapping 
down of the powerfully hinged valves. 
The only other species of this genus known is the 
American Curcinus granulatus (Say), and even this may 
not be really distinct from the European form. 
Portunus, Fabricius, 1798, has the last two joints of 
the fifth legs dilated and compressed, and the last joint 
ovate. It is by this formation that many of the Portu- 
nidee are qualified as swimming crabs. In the Caribbean 
Sea, and among the gulf weed in the tropical Atlantic, 
Mr. Gosse observed them shooting through the water 
almost like a fish, ‘ with the feet on the side that happens 
to be the front all tucked close up, and those on the oppo- 
site side stretched away behind, so as to hold no water, as 
a seaman would say, and thus offer no impediment to the 
way. Our British species swim with less facility, and are 
often called fiddler crabs, because, as Mr. Gosse explains, ‘the 
see-saw motion of the bent and flattened joints of the oar- 
feet is so much like that of a fiddler’s elbow.’ The beauti- 
ful Velvet Crab, Portunus puber (Linn.), called in the 
Channel Islands the Lady Crab, is for ordinary purposes 
sufficiently described by Bell in the ‘ British Stalk-eyed 
Crustacea,’ together with six other species of the genus 
that have been obtained in the waters of Great Britain, 
namely depurator (Linn.), corrugatus (Pennant), arcuatus 
and pusillus, Leach, holsatus, Fabricius, and its near ally 
marmoreus, Leach. To these Canon Norman has added 
Portunus tuberculatus, Roux, from the Shetland Isles. He 
remarks on the singularity of the circumstance that this 
and many other southern forms should be found in the 
deep Shetland waters, though they are not known from 
localities between those waters and the Mediterranean. 
Portumnus, Leach, 1814, both by name and structure, 
closely approaches the preceding genus, but it has the 
