344 PROF. FRANK J. COLE ON THE MORPHOLOGY OF THE MYXINOID FISHES. 



Fig. 8. Section immher 390. x 12^. Colours, etc., as above. The section passes through the anterior 

 process of the hypophysial plate, and through the anterior region of the anterior arch of the dental plate. 

 The numbers refer to the outer row of the ventral teeth — 1, 1', 2, 3 = the anterior and posterior cusps of 

 tooth 1, and teeth 2 and 3. 



Fig. 9. Section number 510. x 14. Colours, etc., as above. The section passes through the thalamus 

 of the brain immediately in front of the infundibulum — -in fact, a small portion of the infundibular cavity 

 appears in the section. The third, fourth, and fifth teeth of the inner row of ventral teeth, and the 

 sixth, seventh, and eighth teeth of the outer row, are indicated by numbers. Cavity of naso-pharyngeal 

 (liypophysial) tube, shaded. 



Plate IV. 



Fig. 10. Section number 720. x 10. Colours, etc., as above. The section passes through the pharynx 

 after the latter has been joined by the naso-pharyngeal tube with its lateral diverticula and also through 

 the base of the velum or pharyngeal valve which projects boldly into the pharyngeal cavity. 



Fig. 11. Section number 840. x 9^. Colours, etc., as above. The section passes through the velum 

 or pharyngeal valve just anterior to the anterior transverse velar bar (cp. Part I., fig. 16, and Part III., 

 fig. 2), and illustrates the relation of the valve to the cavity of the oesophagus, and also the relative 

 position of the "branchial" arches. 



Fig. 12. Section number 2680. x 10. Colours, etc., as above. Eff'erent gill ducts numbered from 

 before backwards. An afferent branchial artery is shown entering the third gill on the right side, 

 and an efferent branchial artery leaving the fourth gill on the left side. The section passes through practically 

 the centre of the gill region (cp. fig. 2), and is intended to illustrate the topographical relations of the 

 thyroid vesicles. 



Fig. 13. Section number 3550. x 10. Colours, etc., as above. To illustrate the relations of the 

 biliary apparatus generally. The figure is diagrammatic in one respect, since the whole of the bile duct 

 does not appear in one section. Its relations are, however, correctly shown. On the left side a dorsal 

 root of a spinal nerve with its ganglion are shown. On the right the section shaves the efferent duct 

 of the thirty-fifth slime sac (counting from before backwards). 



