الفهرس 
الملخص العربى
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Abstract
1.In the present work it was intended to study some of the morphological characteristics of the two Nile fishes A. nurse and A. baremose, in Assiut district and comparing some of the those characteristics of the former species with those of the same species collected from Aswan district, North to the High Dam.
2. The behaviour of the morphometric indices of male,female and combined sex samples of A. nurse, as well as that of the combined sex samples of A. baremose were studied.
3. In all samples of A. nurse and A. baremose, the postorbital index was found to be consistent and its mean value can be used for making a key for identification of such species.
4.In spite of the inconsistency of most morphometric indices of the species studied, they were used to give a preliminary idea about inter-and intra-specific variations. Thus, differentiation between male and female samples of A. nurse, between Assiut and Aswan populations of A. nurse and between Assiut combined sex samples of A.nurse and those A.baremose was possible on the basis of the ranges, means and the behaviour of the morphometric indices.
5.To eliminate the effect of differential growth of different parts of the fish and to establish better grounds to compare fishes of different sizes, regression of some morphometric measurements relative to either the total length or the head length were calculated.
6.The regressions of the morphometric measurements considered in this investigation for Assiut and Aswan male, female, and combined sex samples of A. nurse and Assiut combined sex samples of A. baremose was found to be linear.
7.Comparisons between males and females in each of Assiut and Aswan samples of A. nurse, between Assiut and Aswan combined sex samples of A. nurse, and between assiut combined sex samples of a. nurse and those of A. baremose were carried out by comparing their regression coefficients and the significance of their Y-intercepts.
8. By using some meristic characters sexual dimorphism variability of samples within and between localities and year-to-year variations were investigated to collect evidence about Assiut and Aswan populations of A.nurse. But for the vertebral counts of Assiut samples within the year class 1978 the sex had no effect on the distribution of meristic counts considered. The statistical analysis of vertebral and scale counts revealed that Assiut samples of 1978 represented different local populations whereas each of Assiut samples of 1979 and Aswan samples of 1978 belonged to one and the same local population. The vertebral counts of Assiut samples of A. nurse did not vary from year to year.