GENERATIVE SYSTEM.—The individuals of the present class are, as before stated, of distinct sexes, which in the Dibranchiate order are re cognizable by diversity of size, external form, colour and shape of the internal rudimental shell. In the common Calamary, for example, the gladius of the male is one-fourth shorter, but broader than that of the female.
As only the female organs are known in the Tetrabranchiate order, we are limited in the description of the male parts to those which exist in the Dibranchiate Cephalopods; but from the close resemblance subsisting in the two orders in the form of the organs of the female sex, little, difference can be expected to exist in the structure of the male apparatus.
In the Poulp the male organs consist of a testicle, a vas deferens, a kind of vesicula seminalis, a gland compared by Cuvier to the prostate, the sac containing the moveable fila ments which Needham's description rendered so celebrated, and lastly the penis.
The testicle is situated at the bottom of the visceral sac, and is composed of a membra nous pouch (a, fig. 237), to one part of the inner surface of which are attached a number of branched elongated glandular filaments (b), which swell at the breeding season and dis charge an opake white fecundating 'fluid into the sac. From this cavity the fluid escapes by the orifice (c), and passes into the vas de ferens (d). This is a narrow tube, indefinitely convoluted upon itself; it opens into another larger canal (e), the interior of which is di vided by ridges and incomplete septa; its texture seems to be muscular, so that it pro bably serves by its contractions to eject the fluid carried into it by the vas deferens. From the vesicula seminalis the semen next traverses the extremity of an oblong gland (f) which is of a compact granular structure, and,'like the prostatic or Cowperian glands, contributes some necessary secretion to the fecundating fluid.
Next follows the muscular pouch (g) con taining the filaments or animalcules of Need ham (h). When first exposed, they present
the appearance of white filaments, from six to eight lines in length, packed closely and regu larly in parallel order in three or four rows one above another, from the fundus to the aperture of the pouch ; and they are kept in that position by a spiral fold of the membrane of the pouch, without, however, having the slightest adhesion to that part. For a long time after being removed from their position they continue to exhibit, when moistened, motions of inflection in different 'directions. A short and narrow canal (i) leads from the pouch to the root of the penis (k), which is a short pyramidal body, hollow within, and terminating by a small anterior aperture., In the Sepiola the part corresponding to that called the prostate by Cuvier exists, but is relatively smaller, and the duct by which it communicates with and is appended to the vas deferens is relatively longer ; the sac of the filaments is relatively larger, exceeding doubly the dimensions of the testis; the penis is much shorter.
In the Onychoteuthis the penis is merely grooved, as in the Pectinibranchiate Mollusks, not perforated, and such may be expected to be its structure in the Pearly Nautilus.
With respect to the act of impregnation in the Cephalopods, Aristotle gives two accounts. In the fifth book of the Historia Animaliunz it is stated that the Octopus, Sepia, and Cala mary, all copulate in the same manner ; the male and female having their heads turned to wards one another, and their cephalic arms being so co-adapted as to adhere by the mutual apposition of the suckers. In this act the Poulps are described as seeking the bottom,while the Cuttles and Calamaries are stated to swim freely in the water, the individual of one sex moving forwards, the other backwards. Aris totle also observes that the ova are expelled by the funnel, which the Greeks called physetera (9vanTnecc), and some, he adds, assert that the coitus takes place through that part.