_A._ Of Helix hortensis. The ova (_aa_) are developed on the wall of the follicle, and the seminal masses (_b_) internally. _B._ Of Aeolidia. The seminal portion of a follicle is beset peripherally by ovarian saccules (_a_). _c._ Common afferent duct.] _Cephalopoda._ Lankester (No. 32) has brought out some very interesting points with reference to the nutrition of the eggs of Sepia during their growth. The eggs develop in connective-tissue pouches which early give rise to a double pedunculated capsule of connective tissue. The cells of the inner layer of this capsule soon assume an epithelial character, and become a definite follicular epithelium, while between the two layers there penetrates a network of vascular channels. The follicular epithelium becomes after the establishment of these vascular channels folded in a most remarkable manner. The folds, which are shewn in section in fig. 14, _ic_, project into and nearly completely fill up the body of the ovum. An enormous increase is thus effected in the nutritive surface exposed by the epithelium. Each fold is thoroughly supplied with blood-vessels. The plications of the follicular epithelium give rise to a basket-work tracery on the surface of the ovum. During the stage when the follicular epithelium has the above structure, its cells have a character similar to that of the goblet-cells of a mucous membrane, and pour out their metamorphosed protoplasm into the body of the ovum. [FIG. 14. TRANSVERSE SECTION THROUGH AN OVARIAN EGG OF SEPIA. (Copied from Lankester.) _o.c._ outer capsular membrane. _i.c._ inner capsular membrane with follicular epithelium. _b.v._ blood-vessels in section between the outer and inner capsular membranes. _c._ vitellus. The section shews the folds of the inner capsule with their epithelium, which penetrate into the substance of the ovum for the purpose of supplying it with nourishment.] After the above mode of nutrition has gone on for a certain time a change takes place, and the ridges gradually disappear. This is caused by the epithelial cells passing off from the ridges into the protoplasm of the ovum; and becoming assimilated, after retaining their individuality for a longer or shorter period. When the absorption of the ridges is completed the surface of the ovum assumes a perfectly regular outline. The capsule of the ovum then bursts at the opposite pole to the peduncle, and the ovum falls into the oviduct. The ova of the Cephalopoda, like those of the Gasteropoda, are quite naked, being without a vitelline membrane or chorion. The egg-capsule which is formed for them in their passage down the oviduct is perforated in Sepia by a micropylar aperture. CHÆTOPODA. (33) Ed. Claparède. "Les Annelides Chætopodes d. Golfe de Naples." _Mém. d. l. Sociét. phys. et d'hist. nat. de Genève_ 1868-9 and 1870.