THE AMERICAN LADY-CRAB 67 
last joint of the fifth legs lanceolate. The British species 
which Bell names Portumnus variegatus, Leach, he ought 
in accordance with the rules of priority to have called 
Portumnus latipes (Pennant). In distinguishing Por- 
tumnus from the closely allied blatyonichus, Latreille, 
1818, Bell or his printer has made a confusing mistake 
by attributing to Platyonichus the acutely lanceolate ter- 
minal joint in the fifth pair of legs, and the broad oval, 
very much rounded joint to Portumnus, instead of putting ~ 
the contrast the other way round (see Plate II.). He men- 
tions that in Portumnus, as in many other Portunide, the 
pleon of the male is five-jointed, whereas in Platyonichus 
it is seven-jointed. Unfortunately this distinction, which 
would have been so convenient, only applies to two out of 
the three species which are now allotted to the latter genus, 
namely to Platyonichus bipustulatus, Milne-Edwards, and 
to Platyonichus tridescens, Miers, a species in which the legs 
are said to be beautifully iridescent. 
Platyonichus ocellatus was first described in 1799 by 
Herbst, who records its habitat in the words, ‘ Das Vater- 
land ist Long-Hiland bey Newyorck.’ Both New 
York and the ‘ Lady Crab’ of America have come to be 
better known than they were in the time of Herbst. 
Verrill and Smith, in their valuable report on the inverte- 
brate animals of Vineyard Sound, give a figure of the crab 
and many interesting particulars. It is, they say, perfectly 
at home among the loose sands at low-water mark, and 
also abundant on sandy bottoms off shore. It is a rapid 
swimmer, and was not unfrequently taken on the surface 
of the sea. ‘When living at low-water mark on the 
sand beaches it generally buries itself up to its eyes and 
antennze in the sand, watching for prey or on the look-out 
for enemies. If disturbed, it quickly glides backward and 
downward into the sand, and disappears instantly. This 
power of quickly burrowing deeply into the sand it pos- 
sesses in common with all the other marine animals of 
every class which inhabit the exposed beaches of loose 
sand, for upon this habit their very existence depends 
during stcrms. By burying themselves sufficiently deep 
