46 D. KEILIN 
(c) Superficial or epithelial portion. 
It is a matter of surprise that, in spite of the fact that he 
absolutely condemns Hisen’s observations as to the existence 
of ductules in the pharyngeal epithelium, Stephenson made 
no special study of this particular portion of the pharynx, 
although such study is all-essential for making a correct inter- 
pretation of the function of the pharyngeal gland cells. 
The lumen of the pharynx (Text-figs. 1, 2, and 6, A) in all 
earthworms is divided by means of two longitudinal folds of the 
lateral walls into dorsal and ventral chambers. An elongated 
median slit, bordered by the free margin of these folds, estab- 
lishes a communication between these portions of the pharyngeal 
lumen. The lateral folds meet posteriorly in the median line to 
form a posterior dorsal pharyngeal pocket which communicates 
with the two lateral pockets and forms the dorsal or salivary 
chamber of the pharynx (Text-fig. 1, ph. d., and Text-fig. 6, A, 
ph. d.), while the ventral chamber (ph. v.) is continued into the 
oesophagus (0e). 
Of all the pharyngeal aiheleie the dorsal portion only, to 
which the pharyngeal bulb is attached, is composed of ciliated 
cells. The cells of the remaining portion of the pharyngeal 
epithelium are covered by a thin cuticular layer similar to that 
which lines the oesophagus. 
The dorsal portion of the pharyngeal epithelium of Allo lo- 
bophora chlorotica (Pl. 3, fig. 3) is composed of 
elongated cells, the oval nuclei of which are provided each with 
one or two nucleoli besides the chromatic granulation. These 
cells are usually so crowded that, in sections, their nuclei 
appear to lie at different levels. The free border of the cells 
bears the vibratile cilia (cl.). 
The basal ends of the cells are very narrow and covered with 
a basal membrane. Near the free border of the epithelium one 
often sees the darkly-stained nuclei in all stages of the karyo- 
kinesis. As one follows their approach to the internal surface 
of the pharyngeal epithelium, the mucin ducts (PI. 3, fig. 3, 
d. mu.), which, as we have previously seen, are interlaced with 
