PHARYNGEAL GLAND-OELLS OF EARTHWORMS. 277 
character, are still more definitely confined to the posterior 
and dorsal portions of the mass. They are entirely absent 
from half of the thickness of the mass, — that half which is 
nearest to the pharyngeal epithelium. 
The shape of the cells is, as before, various ; the outlines 
are well-defined, and there is for the most part no shading off 
into an intercellular substance. An average measurement in 
the longest diameter would be 15 fi; 20 would be excep- 
tional. The nuclei are to a considerable degree obscured ; 
they measure 3 ’5 — 4^u in greatest diameter, are vesicular, 
shortly ovoid, with large equably staining nucleolus and 
scattered, sometimes mainly peripheral, chromatin grains. 
The nuclear characters are thus already remarkably like those 
of the adult. The cells are rather loosely arranged, with 
considerable intervals. 
Here and there, in the most deeply placed cells, — those 
which have wandered off a little from the main mass and 
form the outposts of the aggregate, — there is a sli ght 
indefiniteness of boundary owing to the peripheral portion of 
the cell-body becoming disintegrated into granular matter. 
But there is no formation of connective tissue ; the connective 
tissue of the pharyngeal mass at this stage has therefore an 
entirely different origin. This specimen agrees with the last 
described in the nature of this connective tissue of the 
deeper part of the mass, and of its nuclei; and also in the 
absence or very slight and partial development of a capsule. 
Summary of Appearances in Young Pheretimas. — 
In successively younger specimens of Pheretima therefore: 
(1) The cells are more and more confined to the superficial 
portion of the pharyngeal mass. This is strongly suggestive 
of a derivation from the peritoneum ; it is the opposite of 
what, presumably, would happen if the cells were derived 
from the pharyngeal epithelium. 
(2) The disintegration and the transformation of the cells 
into connective tissue is progressively less marked. 
(3) The capsule is less differentiated ; the chromophil cells, 
which in places even in the adult border the coelomic cavity 
