Optic nerve head morphology of the Eastern gray squirrel, Sciurus carolinensis.

The objective of this study was to characterize the morphology of the Eastern gray squirrel optic nerve head, using histochemical techniques and scanning electron microscopy, in order to make comparisons with other mammalian species. Eyes of three Eastern gray squirrels were enucleated, fixed in 10% neutral buffered formalin, and embedded in paraffin. Sections through the optic nerve head were made in the three different planes, and staining was accomplished with hematoxylin and eosin and Gomori's trichrome stain.

Structure and presumptive function of the iridocorneal angle of the West Indian manatee (Trichechus manatus), short-finned pilot whale (Globicephala macrorhynchus), hippopotamus (Hippopotamus amphibius), and African elephant (Loxodonta africana).

The iridocorneal angles of prepared eyes from the West Indian manatee, short-finned pilot whale, hippopotamus and African elephant were examined and compared using light microscopy. The manatee and pilot whale demonstrated capacity for a large amount of aqueous outflow, probably as part of a system compensating for lack of ciliary musculature, and possibly also related to environmental changes associated with life at varying depths. The elephant angle displayed many characteristics of large herbivores, but was found to have relatively low capacity for aqueous outflow via both primary and secondary routes.