I found iron-hæmatoxylin the most satisfactory stain. I stained for a shorter or a longer time--one-half to several hours and longer--and then washed out the sections until under a low power of magnification they appeared quite unstained, the nuclei and a few other parts only appearing darkly stained. Depigmentation I practiced but little. I obtained many of my series almost wholly unpigmented, especially those I cut last. Others, of course, were very heavily pigmented. I am not certain but that alcohol slowly dissolves out the pigment after a long period of preservation. Slight variations in the technique of killing and preserving may also, perhaps, determine the stability or solubility of the pigment, as, of course, also the condition of the pigment at the time of killing. _Anatomy._--For a short epitome of the anatomy of a Cubomedusa and of a Cubomedusan sensory club see p. 2 of the Introduction. _The Distal Complex Eye_--_General_.--The distal (larger) complex eye (Fig. 7) and the proximal (smaller) complex eye (Fig. 13) are so named to distinguish them from the lateral simple eyes of the clubs. The distal complex eye consists of the following parts: a cellular cornea, continuous with the epithelium of the sensory club; a cellular lens (externally cellular and internally often quite homogeneous) immediately beneath the cornea; a homogeneous capsule just internal from the lens, and evidently a secretion from the lens cells; a vitreous body composed primarily of prisms and pyramids just beneath the capsule; and a retina of pigmented cells, with subretinal nerve tissue, ganglion cells and fibers. To my knowledge all observers (except Carrière, who missed the capsule) are quite agreed on the anatomical structure of the distal complex eye as also on the proximal complex eye and the lateral simple eyes.[d] It is on the histological structure of some of the various parts that differences exist. _Cornea._--Little need be said on the cornea except that it consists of flattened cells applied to the outer surface of the lens. It is continuous with the epithelium of the club and evidently a modified portion of this epithelium (Fig. 7). All observers conform to this statement.