264: E. RAY LANKESTER, ON THE 
the movements of the labial segment, which can be retracted 
so as to close the oral aperture, being dependent on muscles 
similar to those existing in each segment of the body, and 
already described. 
The pharyne is a broad somewhat flattened and very 
muscular organ, immediately succeeding the oral aperture ; 
it extends from the second to the seventh ring of the body. 
The upper surface, exposed when a dorsal incision is made, is 
very muscular, numerous radiating digital fibres connecting 
it with the transverse septal muscles; its lateral attachments 
appear to be the strongest, though numerous radiating fibres 
may be also detected on the ventral surface of the organ. 
The outer thick and muscular coat, which thus gives to the 
pharynx its principal muscular power, is of a yellowish-white 
colour, and very vascular. If this be opened and carefully 
examined it will be found to project anteriorly into the 
hollow cavity which it forms, and gives rise to a sort of disc 
or sucker by the action of which, no doubt, the earthy food of 
the worm is drawn into the mouth. A second, much finer 
muscular coat will also be found underlying this denser one, 
and intimately connected with the loose folds of mucous 
membrane which line the pharyngeal cavity. In fig. 3 a 
small bundle of muscular fibres from the pharynx is drawn ; 
they present the same simple structure and appearance as 
the muscular tissue from all parts of the body. 
Salivary glands.—Opening into the mouth and pharyngeal 
cavity are three pairs of glands, which must be considered as 
salivary organs. Morren appears to have figured these, and 
Mr. Lockhart Clarke briefly mentions their existence. They 
are in the form of convoluted tubules, situated near the oral 
aperture in connection with the dense exterior coat of the 
pharynx, and require a little examination to be detected. 
Passing down the alimentary canal, we come to the @so- 
phagus. This commences in the eighth segment of the body, 
(fig. 5, ce, fig. 6), and is directly continuous with the muscular 
pharynx. The latter organ contracts very considerably in 
the seventh ring, and then is followed by this narrow, delicate, 
but highly elastic tube. The cesophagus extends to the 
fifteenth or sixteenth ring; throughout it is composed of a more 
or less delicate muscular coat and an inner mucous lining. 
In its passage through the septal muscles it becomes slightly 
constricted, and the fibres of the one organ appear to become 
interwoven with those of the other ; this is more particularly 
the case in the eighth, ninth, and tenth rings. The large 
dorsal vessel which runs all along the alimentary canal 
attains its greatest development in the region of the cso- 
