الفهرس 
The macrostructure of the platesOnly 14 pages are availabe for public view
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Abstract
The present study is divided’into 3 main parts and the obtained results in these parts can be summarized as follow: 1- The microstructure studies of four balanid species (Balanus eburneus, B. amphitrite, B. balanoides, and B. perforatus) revealed the dissimilarity between the crystals’s shape, the arrangement and the shape of teeth. In case of B. perforatus which live in (Red-sea), the ciystals’ shape is different fkorn that found in the shell of the same species from Suez canal. The main obtained results can be illustrated in the following points. 1- The shell consists of a ring of overlapping calcareous plates in the form of truncated cone. 2- The wall plates are divided to 5 essential parts, opercular plates (2 terga +2 scuta), Rostrum, carina . carinolateral plates and Rostolateral plates. 3- Each plate is formed of 3 parts, outer lamina, longitudinal tubules and Inner lamina. Except terga and scuta doesn’t include longitudinal tubules. 4- The marginal teeth and septums have a special shape and arrangement in each species . 5- The externalgrowth patterns are diffrentiated into :- fine surface ridges, prominent ridges, 6- The crystalline structure of outer lamina resemble to the inner lamina in the same species but it differs from species to another. Disorientated granular structure in B. eburnens, disorientated prismatic structure in B. balanoides, radiating larnellar structure in B. amphitrite, and disorientated prismatic structure in B. petforatus L which live in suez-canal. It was observed that when the same species living in Red -sea. the crystals take the form of smooth fibers which taking the shape of tight webs of network in the outer lamina only. 7- The internal growth patterns were seen in the thin section as broad lines including helines.