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Show 19910 LARYNX OP CERTAIN WHALES. 281 contrasts very strongly with that of the Odontocete. There is no special means for " locking" it into the narial canal, though its free end is inserted into the posterior nares, in the manner so well known for Cetacea and several other Mammals. The epiglottis is 3 inches long in this young Borqual: its postero-dorsal surface is grooved, the sides of the groove being thick and rounded near the apex, but becoming thinner as they pass into the aryteno-epiglottid folds. The groove is, near the end, narrow and almost slit-like, the lips being closely pressed together in a state of rest. Along the floor of this groove is a ridge, which commences about one inch from the tip of the epiglottis, and increasing in height as it passes backwards, is continued into the sublaryngeal pouch (see below) for a short distance and then gradually dies out. The arytenoid bodies project upwards from the floor of the pharynx to a height of only 1| inches; they are sufficiently high just to enter the posterior nostril, though when food is passing along it appears as if, with the distension of the pharynx, the arytenoid bodies would not reach the nostril. (Plate XXVII. fig. 21.) But as Carte and Macalister show, the extensive muscles are so arranged as to pull the whole larynx upwards during the process of respiration. The two bodies are united posteriorly, and this point is somewhat recurved, but their anterior dorsal margins are free and enclose a deep groove-a groove that, becoming deeper, leads downwards into the laryngeal chamber, which is entered through a large oval aperture, the sides of which are supported by the posterior processes of the arytenoid cartilages. (Plate XXVIII. fig. 23.) The epiglottidean furrow, on the other hand, leads downwards into the " sub-laryngeal pouch." This is a long tubular sac, ending blindly behind, provided with thick muscular walls, and lined with a smooth mucous membrane, which laterally is somewhat folded and trabeculate. This pouch lies on the ventral aspect of the larynx between the two cornua of the cricoid cartilage. (Plate X X V . fig. 1 a.) The ventral wall of the pouch is formed by muscle, its dorsal wall by the arytenoids, between which the pouch communicates, by a wide aperture, with the laryngeal chamber. The sub-laryngeal pouch is essentially a caecal diverticulum of the ventral wall of the larynx, between the thyroid and cricoid cartilages. (Plate XXVIII. fig. 24.) It exists in Balcena, though the musculature there seems to be somewhat differently arranged according to the account given by Eschricht and Bernhardt. Whether it is homologous with the sacs present in several other mammals seems extremely doubtful. (See below.) Carte and Macalister (p. 233) describe a " hood-like fold " of the mucous membrane of the floor of the pharynx just in front of the root of the epiglottis. This I have not seen. M y figures (21-24) were drawn from the fresh animal, before I had looked up any literature on the subject; but I do not think I should have |