1867.] DR. A. MACALISTER ON GLOBIOCEPHALUS 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 sphincter- 

 like 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 Balainoptera 

 the glottis differs remarkably in being arranged in a freer manner, 

 as two-thirds of the prominent portions of the arytenoids and epi- 

 glottis are perfectly unattached to each other. 



The opening of the oesophagus was marked by a sudden con- 

 striction, and was placed below the level of the cricoid cartilage, 

 which was deficient anteriorly. 



The pharyngeal mucous membrane being removed, the three con- 

 strictors 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 quadri- 

 lateral 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 ani- 

 mals, and rarely of man) ; 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 sur- 

 face 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 j)OSterior border of 

 the palatine bone and from a dense fascia, corresponding to an in- 

 wardly 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. pi. 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 



