PHARYNGEAL GLAND-CELLS OF EARTHWORMS. 
259 
return to these at a later date. Nor need I refer to a 
number of observations on the occurrence, form, and position 
of the pharyngeal and septal glands of earthworms by 
systematic writers, since these do not deal with their intimate 
structure. 
The cells in question, therefore, are usually considered 
as gland-cells belonging to the epithelial layer of the 
alimentary tube, and they are supposed to pour their secre- 
tion into the lumen of the tube by means of long, fine 
ductules prolonged from the cell-body. Clapar&de saw no 
ductules, and believed the cells on the pharynx to be nervous 
in nature ; Yogt and Yung, who nevertheless believed the 
cells to be secretory, could not discover the ductules ; Raff 
also saw no duct; Vejdovsky saw “long ducts,” but not, 
apparently, their connection with the pharyngeal cavity ; 
de Ribaucourt saw the continuation of the cells as far as the 
pharyngeal epithelium ; Eisen has given detailed accounts of 
the ductules, of their branching in the pharyngeal epithelium, 
and of their discharge pockets ; Perrier (according to 
Vejdovsky) saw the ducts with a lens, and observed their 
paired orifices. 
According to my observations the cells in question are not 
of epithelial origin, and have no connection with the pharyn- 
geal epithelium. They originate at the peripheral limit of 
the pharyngeal mass, and are congeneric with the peritoneum ; 
in the adult they extend deeply into the pharyngeal mass, 
and there become largely transformed into connective tissue ; 
but what their primary function is I am unable to say. It 
will save repetition to state here that in none of my sections, 
which were taken in all three planes, have I seen structures 
that could be interpreted as ductules. 
Claparede’s view of the nervous nature of the cells prob- 
ably originated in their superficial resemblance to the spinal 
ganglion cells of higher Vertebrates; there is no resemblance 
to the ganglion cells of the Oligochaeta. Vejdovsky’s state- 
ment as to the similarity to the coelomic corpuscles of those 
