The ova which are contained in the mem branous part of the oviduct of the Sepia, consist of a deep yellow vitellus, inclosed, first, in a very delicate vitelline membrane, and, externally, in a thin, smooth, shining, easily lacerable, cortical tunic, or chorion. VVe have generally found them in great num bers, squeezed together in a mass, so that few retained their true form.
The external tunic of the ova in Rossia is stronger than in Sepia, and the form of the ovum, which is elliptical, is consequently bet ter preserved : the oviduct, in the specimen dissected by us, contained several ova detached from one another, in progress of exclusion, as represented in the figure at f, 1 The ova in Sepiola, as in the two preceding genera, are devoid of any external reticulate markings, which belong only to the ovisac or formative calyx.
The delicate ova are defended by additional layers of a horny substance deposited on their external surface by the terminal gland, which may be compared to the shell-secreting segment of the oviduct in the Fowl. When the ova quit the oviduct, they are connected together by, and probably receive a further covering from, the secretion of the two large super added glandular bodies (g, g, fig. 239), the wide ducts of which converge and open close to the termination of the oviduct.
Then bodies, in the Cuttle-fish, Sepiola, and Rossia, are of a pyriform shape with the apices, converging and turned forwards; of large size, especially at the reproductive season, situ ated on the ventral aspect of the abdomen, but not attached, as in the Nautilus and in ferior Mollusks, to the mantle. They are each composed of a double series of transverse, parallel, close-set semi-oval laminm, the straight margins of which are free and turned towards each other along the middle line of the gland. When the gland is laid open, an impacted layer of soft adhesive secreted sub stance is found occupying the interspace of the two series of lamin2e ; m which, in Rossia, it is evidently moulded into a filamentary form, whence it escapes by the anterior orifice above mentioned. (See h, h, fig. 239.) The laminm are attached by their convex margins to the capsule of the gland, which is thin, and probably contractile; it is com pletely closed at every part save the anterior outlet, forming a shut sac posteriorly, and having no communication with the oviduct or oviducts, for which these glands have some times been mistaken.* In the Cuttle-fish the extremities of the ovarian glands rest upon a soft parenchymatous body of a bright orange colour : the correspond ing part is rose-red in the Sepiola, and of a bright colour in all the congenenc species. In
the Sepia this body is trilobate, consisting of two lateral slightly compressed conical portions, whose obtuse apices are directed forwards, and a smaller middle portion connecting the lateral ones at their posterior and internal angles. The dorsal surface of the lateral lobes is flat tened, the opposite side excavated to receive the superincumbent extremities of the ovarian glands. To these the substance in question is closely attached by a tough connecting mem brane, but has no correspondency of structure nor any excretory outlet. Its texture is dense and granular, with minute cells, the largest of which are in the centre of the body, and are filled with a yellowish brown caseous substance. In Sepiola the corresponding body is single, and is similarly attached to the anterior extre mities of the two nidamental glands. In the Loligines and in Rossia it is double ; each portion (i, i, fig. 239) in the latter genus is at tached by cellular tissue to the anterior part of its corresponding nidamental gland, and is excava ted by a deep groove close to the aperture of the gland : from this structure and their position it would appear that they assisted in moulding the nidamentum, and, perhaps, in applying it to the ova. Considering the texture of these singular bodies, their ordinarily bright colour, and their relative position to the generative apparatus, we believe ourselves justified in regarding them as the analogues of the glan duke succenturiatee or 4 supra-renal bodies' of the Vertebrate animals.
In the Octopodous Dibranchiates the ovary is a spherical sac with thick parietes (1,fig. 226).
A Ile V VISitl:b kZ) 1-ZUXIIIVbe VI CV1111eCieU bunches and attached in the Poulp to a single point of'the ovarian capsule, but in the Eledone to about twenty separate stalks suspended from the upper part of the ovary. The ova, when detached from the ovisacs, escape by a single large aperture (3), leading from the anterior part of the sac into a very short single passage, which then divides to form the tvvo oviducts. These tubes, in the unexcited sta.te of the ge nerative system, are membranous, straight, and of an uniform narrow diameter, except where they perforate a glandular laminated enlarge ment (4), situated about one-third from their commencement; but, towards the period of ovi position the parietes of the oviducts increase in thickness and extent, forming longitudinal folds internally.