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Show 1867.] DR. A. M A C A L I S T E R ON G L O B I O C E P H A L U S SVINEVAL. 479 the canal; so the tube was single at its pharyngeal end for a short distance ; its mucous walls were thick and slightly moveable, having a muscular ring subjacent to the lining membrane. This sphincterlike arrangement arose from the median ridge of the basisphenoid, and surrounded the aperture of the nares; from its position it was evidently a displaced representative of the levator palati muscle; here, however, it is developed as a constrictor naris. Below, the pharynx contained the tubular prolongation of the glottis, which in this species resembled that of the Porpoise in the cohesion of its sides, as the aryteno-epiglottidean folds were prolonged nearly to the extremities of the arytenoid bodies and of the epiglottis; these folds contained the aryteno-epiglottic muscles. In Balcenoptera the glottis differs remarkably in being arranged in a freer manner, as two-thirds of the prominent portions of the arytenoids and epiglottis are perfectly unattached to each other. The opening of the oesophagus was marked by a sudden constriction, and was placed below the level of the cricoid cartilage, which was deficient anteriorly. The pharyngeal mucous membrane being removed, the three constrictors were exposed, arranged nearly in their usual manner. The inferior had its origin from the posterior margin of the cricoid and thyroid cartilages, and was inserted into the median raphe; below it were the inferior laryngeal nerves; and in shape it was quadrilateral and very narrow. The middle constrictor was rather thicker and somewhat triangular; it arose from the posterior cornu of the hyoid bone and by some fibres from the stylo-hyoid cornu (the latter corresponding to the occasional syndesmo-pharyngeus of some animals, and rarely of m a n ) ; its fibres ran backwards, expanding, and were inserted into the median raphe, where they were wide and thin and overlapped by the last described. The superior constrictor, whose fibres were closely connected to those of the palato-pharyngeus, formed a thick stratum surrounding the anterior extremity of the pharynx; it arose from the inner surface of the internal pterygoid plate, extending into the posterior nasal orifice to a distance of 3 inches from the pharyngeal level of that opening; its fibres likewise arose from the posterior border of the palatine bone and from a dense fascia, corresponding to an inwardly displaced intermaxillary ligament, which extends from the angle of the maxilla to the edge of the stylo-hyoid cornu ; from these origins the fibres ran downwards, inwards, and backwards to be inserted into the raphe. The most internal fibres were continued over the others, and on a plane superficial to the middle and even to the inferior constrictor; these, though in this instance inseparable from the rest of the mass, yet, from the nature of their insertion, I would judge to be the representative of the muscle not infrequent in some animals, and called by Meckel azygos pharyngis. This muscle sometimes occurs as an irregularity in human anatomy (Proceedings of the Royal Irish Academy, vol. ix. pl. 5. f. la). Within the constrictors, although there was no distinct posterior faucial pillar in relation to the soft palate, yet there was a strong |