THE GRANULOPOIETIC ORGANS OF THE NARROW NOSE SMOOTH HOUND Mustelus schmitti (CHONDRICHTHYES, TRIAKIDAE). A LIGHT AND ELECTRON MICROSCOPIC STUDY

the elasmobranchs are important natural models of hemopoiesis since they possess naturally dissected the inductive microenvironment. in this study we describe the general structure and cellular morphology of the two principal granulopoietic foci of mustelus schmitti (springer, 1936): the leydig and the epigonal organs, likewise we semiquantify the hemopoietic compartments. myeloid cells pertain to three different lineages. the principal nonmyeloid cells are lymphocytes, macrophages and reticular cells. no erythropoietic or thrombopoietic elements were found. the general structure of both organs is similar to those of other selachians, but their size and cellular diversity is typical for this species. better knowledge of the stromatic environment of these specific hemopoietic organs may give further insight on the nature of their specific inductive functions