Penaeid prawns of Ceylon (Crustacea Decapoda, Penaeidae)

INTRODUCTION Penaeid prawns form the basis of flourishing fisheries in South America, East Africa, India, Ceylon, Hong Kong, Indonesia and Australia. In some of these countries surveys are in progress to determine new prawn resources in the sea, since the demand for these crustaceans is unsatisfied. The scientific study of these animals has progressed considerably in most of these areas. Studies in the Indian region can be referred to in the works of Alcock, 1905, 1906; Bate, 1888; De Man, 1888, 1911; Henderson, 1893; Kemp, 1915 and Miers, 1884. Some of these authors have made passing references to the species present in Ceylon waters, but the only special study of the Ceylon species is that of Pearson (1905). Pearson's article, however, refers only to nine species, about half of them marine, while the commercially abundant species of lagoon waters have been neglected. The present article deals with the taxonomic study of thirty-one species. The nomenclature has been critically revised in relation to recent changes and comparisons have been made with con-generic species from other parts of the Indo-Pacific. The distribution of species in Ceylon waters is discussed in relation to its bearing on the hypothesis put forward by Hall (1958) on the distribution of Penaeidae in the Indo-Pacific region as well as in relation to environmental conditions. The examined material is now placed in the collection of the Fisheries Research Station at Colombo and in the collection of Decapod Crustacea of 1) Formerly of the Fisheries Research Station, Colombo, Ceylon. the Rijksmuseum van Natuurlijke Historie at Leiden. In the following text