The initial paper in this series described the fine structure of Bruch's membrane in the human, monkey, rabbit, rat, and guinea pig.1 Bruch's membrane in animals possessing a tapetum—the cat, dog, and cow—were also studied and will be described in this paper.
Bernstein and Pease,2 in a study of the ultrastructure of the cat tapetum cellulosum, defined Bruch's membrane as a layer 1.0μ to 4.0μ thick with two components: (1) the basement membrane of the retinal epithelium (the homogeneous component), and (2) a fibrous layer interposed between the retina and the tapetum (the reticular component). They found thin basement membranes associated with both the capillary endothelium and the retinal pigment epithelium. In areas where the tapetum was absent, these membranes were separated by a collagenous layer that varied in thickness but was continuous over the inner surface of the choroid and between the tapetum and capillaries. These authors