PRELIMINARY OBSERVATIONS ON THE EARLY EMBKYONIC DEVELOPMENT OF RAN SPINOSA

This paper deals with the early embryonic development of Rana spinosa The wholeprocess of embryonic development took about 234 hours and may be divided into27 stages(includes:1.fertiluzed egg,2.2-cell stage,3.4-cell stage,4.8-cell stage,5.16-cell stage,6.32-cell stage,7.64-cell stage,8.multicellularstage,9.early-blastu-la stage,10.late-blastula stage,11.early-gastrula stage,12. mid-gastrula stage,13.late-gastrula stage,14.neural plate stage,15.neural folds stage,16.ciliary movementstage or rotation stage,17.neural tube formation stage,18.Muscle functioningstage,19.heart beat stage, 20.outer gill formation stage,21.tail fin membraneappearance stage,22.Crystalline lenses formation stage,23.eyeball pigment stage,24.body pigment appearance stage,25.gill cover fruition stage,26.hatching stage,27.egg yolk complete absorption stage). In our experiments the water temperaturewas controlled at 25.15±0.22℃. A time table for the development and descriptionsof embryonic feature are also given in this paper.