Opening ParagraphThe Ibo-speaking people of Eastern Nigeria can be regarded as a single culture area which may provisionally be subdivided into five main divisions: Northern or Onitsha, Southern or Owerri, Western or Ika, Eastern or Cross River, and North-eastern or Abakaliki. The first two divisions, whose boundaries correspond very roughly to those of the Administrative Provinces of Onitsha and Owerri, contain the bulk of the population; the Western occupies the Niger riverain region and the forest country beyond, and their culture has been influenced by that of the Edospeaking tribes farther west, and by Benin; the Cross River Ibo are another marginal group whose affinities with the ‘Semi-Bantu’-speaking tribes on the eastern bank of that river have yet to be studied; while the North-eastern Ibo are a specialized group that has developed, in comparative isolation, a culture and a social structure better adapted to the savannah country in which they live. The remarks which follow refer mainly to the Northern, Southern, and Cross River Ibo; the North-eastern Ibo system differs in many important respects; the Western has not been studied. The terms used in defining Ibo social groupings have been explained in Africa, vol. xix, No. 2, p. 151, and in places where this may cause confusion the ‘official’ or alternative term is given in brackets.
QUANTIFICATION OF THE SINUSOIDAL TRAJECTORY IN TISSUE MASS AND CONDITION INDICES OF A BIVALVE (EGERIA RADIATA) IN THE CROSS RIVER, NIGERIA*