These results are not wholly satisfactory, for they leave us with three kinds of fibrous processes in the vitreous body which for the present we are unable to trace to three, or even two distinguishable types of cell in the retina. It would be more pleasing if we could confirm Schewiakoff’s simple conception of the structure, with its one set of visual rods in the vitreous body referable to a clearly marked type of sensory cells in the retina, but I think the evidence that has been brought up justifies the conclusion that in some respects he saw too much, in other respects too little. This is not to be wondered at, since his material, to judge from a single statement, consisted of but twelve marginal bodies, and, moreover, the work on Charybdea forms but one portion of a paper that is excellent for the clearness of its descriptions and illustrations. Before leaving the subject I must mention that Wilson suggested from his observations on Chiropsalmus that the vitreous body had a prismatic structure, but he was probably mistaken when he thought he found evidence of nuclei in it. Claus says that the retina is composed of pigment and rod cells alternating, and Wilson agrees with him, but under a sketch of a sense cell from the nerve he makes the express statement “not very well preserved.” It seems very probable, therefore, that he followed Claus’s interpretation rather than independent observations, and Claus interpreted his results very much by analogy of what had been found in other forms. The smaller complex eye which is represented in Fig. 69 agrees in structure very closely with the larger. The chief differences are that sections do not show pigment extending into the vitreous body, that there is no “capsule” to the lens, and that the lens seems to be supported by a kind of stalk formed by a thickening of gelatine of the supporting lamella (_sl_). The gelatinous thickening lies between the lens and an outgrowth of endodermal cells (_en_) from the canal of the club. This outgrowth is a constant feature, figured by Claus and Schewiakoff for Charybdea, and by Wilson for Chiropsalmus, and found in Tripedalia also. The regularity of its appearance in all three genera leads one to suspect that it may have some significance not yet understood.