Antennular plate with 2 strong spines, without scattered small spinules. Third maxilliped without exopod. Abdominal somites 1 to 6 with a distinct uninterrupted white transverse band along posterior margin. Surface abdominal somites naked, smooth, without transverse grooves.
Colour: abdominal somites 2 to5 with a white transverse band along posterior margin which, however, is not set off by dark bands. Colour of body and abdomen usually greyish green without spots. Tail fan of a rather uniform colour. Legs irregularly spotted, not distinctly streaked.
Type locality of Cancer polyphagus: "Das Vaterland ist Ostindien". The dry holotype or lectotype in ZMB, no. 1973, in good condition.
Type locality of P. fasciatus: Habitat in Oceano Indico Dom. Daldorff". I.K. Daldorff, a Danish officer at Tranquebar, S.E. India, collected there for Fabricius and also Herbst obtained material from him. The type material of P. fasciatus almost certainly came from the Tranquebar area, and there even is a possibility that Herbst's material of C. polyphagus was also obtained from Daldorff, so that the type localities of the two species would be very close, but this is only a guess. Three syntypes of P. fasciatus are in UZM, preserved in alcohol, condition reasonable.
The statement of the type locality of P. orientalis is: "Japan. Salmin". Balss (1914: 76), who examined Doflein's type specimen and synonymized P. orientalis with the present species, remarked that the locality indication "Japan" is doubtful "da auf Salmins Fundorte in unserer Sammlung kein Verlass ist" and as the species was not known from Japan. C.L. Salmin was a dealer in natural history objects in Hamburg in the second half of the last century (the Leiden Museum had dealings with him between 1863 and 1875) and evidently, like several of such dealers at that time; was not very accurate with labelling his material. The true type locality of P. orientalis thus is unknown; the holotype was in ZSM, now probably lost (not located in 1989).
Indo-West Pacific region, from the coasts of Pakistan and India to Vietnam, the Philippines, Indonesia, N.W. Australia and the Gulf of Papua.
Habitat and Biology:
The species is found on muddy substrates and sometimes on rocky bottoms. Often found near river mouths, in turbid water. Depth range from 3 to 90 m,but usually far less than 40 m.
Maximum total body length: about 40 cm, common from 20 to 25 cm.
Interest to Fisheries:
In the Bay of Bengal and the Gulf of Thailand, the species is quite important commercially. In India, the main fishing season extends from November to March. The animals are caught by trawling, but also with set nets, seines, etc.; they rarely enter traps. Sold fresh and frozen in local markets and also transported to the larger towns. Served regularly in restaurants in Thailand, and elsewhere. In Thailand, mounted dry specimens, usually in fancy glass cases, are sold as curios to tourists.
As the specific name fasciatus formerly has often been used not for this species but for P. versicolor, old records of P. fasciatus have to be treated with much reserve.