الفهرس 
Morphological studiesOnly 14 pages are availabe for public view
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Abstract
Patently sympolic of marine life,the isopods represent one of the celebrated and curious denizens of invertebrate world. Approximately 10,000 species of isopods have been identified from littoral and benthic areas throughout the world (Schultz, 1982) . Isopods surpass other crustaceans.not only in the number of species and individuals,but also in the diversity of habitats. Since,it is the only crustacean group which live in all major habitats including marine and freshwater as well as terrestrail where some of them are well adapted for parasitic life . On the other hand, because in the present day new techniques,used for identifying the different animals,it is highly probable that some taxonomical variations will certainly be existed between already identified species . For the previous reasons and also because isopods are much common crustacean members inhabiting Egyptian fauna and our knowledge of various aspects of these animals is ,however ,not satisfactory ,this thesis was planned. The present investigation is an up to date attempt for identification of marine isopods inhabiting Egyptian water .It was designated on the basis of two parts , the first part concerns with the identification of the collected species using scanning electron microscope,while the second part deals with the cytological studies of the identifed species. The present work was conducted during the period from February.1988 to August,1989. The specimens were collected from different locatities representing most Egyption shores namely;Suez,Ismailia,port-saied and Alexandria. Seven species of crustacean isopods were identified during this thesis. The species are Cirolana bovina ,Cmodoce truncata,D~namene bidentata,Paracerceis ~cul~t4, S~haeroma serratum,S~haerom walkeri and Svnidotea variesate .These identified species belong to 2 subords, 3 families and 6 genera. The conclusion arised from systematic account , by using scanning electron microscopy , drawn that there are several additional characters in each of the identified species which could not be seen by using normal light microscope. The importance of these characters from the taxonomical point of view required further investigations on all isopods to put our hand on all variations to give our suggestion on the exact relation between all isopods. The best results were obtained from gonads. The karyotypic analyses of the studied species revealed the following results: 1. Cirolana bovina: The diploid chromosome number (2n) is 40. The karyotype consists of 9 metacentric pairs, 9 submetacentric pairs and 2 subtelocentric pairs. 2. Cvmodoce truncata: The diploid chromosome number (2111 is 52. The karyotype analysis revealed that 16 pairs of chromosomes are metacentric, 9 pairs are submetacentric and only one pair is subtelocentric. 3 . Paracerceis sculpts: The diploid chromosome number (2n) is 48. The analyzed karyotype showed only two types of centromeric positions including 17 metacentric pairs and 7 submetacentric pairs. 4. S~haeromq serraturn: The diploid chromosome number (2n 1 is 78. The karyotype consisted of 29 metacentric pairs, 8 submetacentric pairs and 2 subtelocentric pairs. 5. S~haecroma walkeri: The diploid chromosome number (2111 is 62. The karyotype consisted of 27 metacentric pairs and 4 submetacentric pairs. chromosomal analysis technique have been attempted with Dvnamene bidentata and Svnidotea variesata, but was not successuful due to the smaller size of the first species and the few numbers of individuals collected from the second species. from the view point of cytology it can be generally said that the present study revealed that the chromosome nubmers and karyotypic analyses of the investigated isopod species are very clearly different.