300 OK THE LARYNX OF CEETAIK WHALES. [Apr. 2, 



Fig 2 Dorsal view of the larynx of the same. Some of the muscles have 

 ' been removed from the right side. Note the continuity of the upper 

 tracheal rings with the cricoid cartilage. 

 Fio- 3 Yiew of the right side of the larynx of the same. 



Fie- 4*. Coqia. Ventral view of the larynx, the extrinsic muscles of the left 

 ' side having been removed. The thyroid cartilage is seen to consist 

 of separate right and left alaj or plates, which have been somewhat 

 forced apart in order to show the subepigiottid cartilage. 



On the left side, the tendon ( W. on the right) had been cut away 

 so that the small crico-thyroid muscle is partially exposed. 

 Fig. 6. Dorsal view of the larynx of the same. 



Plate XXVI. 

 Fig. 6. The larynx of Cogia from the right side. 

 Fio-. 6 a. Aperture of the same, showing the small crico-thyroid muscle, the 



outline of which is dotted, where it is hidden by the thyroid cornu. 

 Fio-. 7. BalcBiwptera. The cricoid cartilage from the ventral surface. 

 Fig. 8. Cogia. The cricoid cartilage (ventral view). 

 Fig. 9. The same, dorsal view. 

 Y\o. 10. The same, side view. r. ridge, along which the lateral crico-arj'tenoid 



is inserted. 

 Fig. 11. Balcsnoptera : the epiglottid cartilage from within (i. e. dorsal surface). 



a, the u-pper and b, the lower region. 

 Fig. 12. The same, side view, hi sitio {cf. fig. 17) : a, h, transverse sections of the 



epiglottid cartilage. 

 Fig. 13. Cogia. The epiglottis from the side. 



Plate XXVII. 



Fig. 14. The epiglottis of Cogia from within : a, h, transverse sections at the 

 levels similarly marked. 



Fig. 15. Balmnoptera. The right arytenoid cartilage from without. 



Fig. 16. Cogia. The right arytenoid cartilage from without. 



Fig. 17. Balcsnoptera. The aryteno-epiglottidean apparatus, seen after removal. 

 of the right half of the thyroid cartilage. 



Fig. 18. Cogia. Tue aryteno-epiglottidean tube, from the right side, after 

 removal of the right ala of the thyroid. The cricoid cartilage had 

 been cut and the epiglottis has sunk downwards slightly. 



Fig. 19. Cogia. The inner face of the left thyroid plate, showing muscle 

 attachments. 



Fig. 20. Cogia. The entrance to the larynx, at the apex of the aryteno- 

 epiglottidean tube. 



Fig. 21. Balcenoptera. The right side of the pharynx has been cut through, and 

 carefully lifted without disturbing the relations of the epiglottis and 

 palate. 



Plate XXVIII. 



Fig. 22. Ba.lcBnoptera. The same as fig. 21, after the depression of the floor 

 of the pharynx, so that the entrance to the larynx is displayed. 



Fig. 23. Balcenoptera. The sublaryngeal pouch has been opened by a longitudinal 

 incision ; the right arytenoid has been tnrned upwards so as to open 

 out the groove between them and expose the glottis, the opening 

 between the pouch and the larynx. This aperture (0.) is placed 

 between the posterior processes of the arytenoid cartilages. 



Fig. 24. Balanoptera. Outline of larynx, supposed to be transparent, so as to 

 exhibit the extent and relations of the sublaryngeal pouch and the 

 cavity of the larynx : the contained cavities are shaded. 



Fig. 25. Cogia. View of the interior of the aryteno-epiglotlid tube, as seen 

 when it has been opened by an incision separating the right arytenoid 

 from the epiglottid. It is seen that there is no median sac at the 

 base of the epiglottis. 



Fig. 26. Zifhius, sp. A median longitudinal section through the larynx. 

 t, tubular outgrowths from the lateral pouches ; s, membranous 

 septum separating the right and left pouches.. 



