Abstract
The general structure of the spleen of the Afghan pika (Ochotona rufescens rufescens), recently noticed as a new laboratoly animal of Lagomorpha, was studied by light and electron microscopes. Scanning electron microscopy of micro corrosion casts was also used to visualize microvascular pathways in the pika spleen. The basic cellar compartments of the pika spleen and intrasplenic micro circulations were similar to those of rabbits, but active extramedullary myelopoiesis was noted in the splenic cords of adult pikas. It was also notewarthy that the marginal sinus had perforated wall as well as the splenic sinus wall in the pika spleen. Scanning electron microscopy of vascular casts suggested that mostly open routes existed in the red pulp, and both open and closed circulation did in the marginfal zone, though a possibility as a functionally closed circularation may remain. The marginal sinus was initially suggested to function as a filter against foreign particles or antigenic materials, because masses of resin and carbon particles injected intravenously leaked out firstly from the marginal sinus wall and further, the marginal sinus had perforated wall.
