PORTUMNUS. 
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Gen. 13. PORTUMNUS, Leach, 
Tarsus of hind legs very wide, lanceolate. Carapace longer 
than wide, and much contracted behind ; front with one of 
the teeth on the middle line ; a single fissure on the upper 
orbital margin. Abdomen of male with five segments. 
Tarsus of second, third, and fourth pairs of legs narrow 
and not adapted for swimming. 
Portumnus latipes, Penn. sp. Pennant’s Swimming 
Crab . — Carapace with the latero-anterior margins furnished 
with very small teeth; front legs short. It is of a dull 
purplish-white, mottled with a darker hue. Pound on the 
south and west coasts of England and on the Irish coasts. 
In Scotland it has been found on the shores of the Pirth of 
Porth and of the Moray Firth. The Rev. G. Gordon re- 
marks that it seems never to move so far from the land as 
to become the prey of any of the more rapacious fish. 
Gen. 14. POLYBIUS, Leach. 
Carapace nearly circular, the legs all flattened ; the tarsi 
of second, third, and fourth legs wide and lanceolate, those 
of the fifth oval. 
The Rev. Alfred Norman informs me that he has seen 
