ON ONCHNESOMA STEENSTRUPII. 249 
Fic. 8.—Transverse section through the introvert, showing the layers of 
the skin, the cesophagus, retractor muscle, and ventral nerve-cord. The 
body-cavity contains corpuscles and sperm morule, 
Fie. 9.—Longitudinal lateral section of the extended introvert, showing 
mouth, oesophagus, and thickened ciliated lip, with the circum-csophageal 
nerve of each side. 
Fic. 10.—A section of the brain, parallel to the preceding (fig. 9), but more 
dorsal. It shows the distribution of the ganglion-cells and fibres in the brain, 
and the three main nerves given off from it ; also the insertion of the retractor 
muscle, and one of the recesses formed by the crumpled nature of the 
cesophagus. 
Fie. 11.—Diagram representing the arrangement of parts in the head, 
which is supposed to be divided medianly. The right half only is shown. 
Fre. 12.—Section through the head and brain. The introvert is retracted. 
The section is not quite in the middle line, and does not show the connection 
of the brain with the epidermis. 
VOL, XXXIII, PART II.—NEW SER. R 
