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be recognised ; but in general even the deepest cells retain 
their original characters. 
The cells cease altogether some distance from the pharyn- 
geal epithelium ; in other words, they have not yet distributed 
themselves throughout the whole pharyngeal mass. Near the 
pharyngeal epithelium and between the interlacing muscle 
fibres are scattered nuclei belonging to the sparse con- 
nective tissue of this region. These nuclei are of various 
and sometimes of irregular shape, and scarcely any structure is 
to be made out in them; the connective tissue, reticular or 
amorphous, is non-staining ; and there is no transition between 
this tissue and the chromophil cells. It represents the 
ordinary connective tissue of the muscle, and is comparable 
to the connective substance between the muscle fibres in the 
body-wall, or in other regions of the alimentary tube. The 
adult connective tissue of this region has, therefore, as pre- 
viously surmised, a double origin. 
For the greater part of the surface of the mass there is 
nothing of the nature of a capsule; the margin of the mass 
is the distinctive cytoplasm, coarsely granular in character, of 
the chromophil cells, and there is an entire absence of any 
superficial differentiation, or of any special covering. In 
places however a little pinkish-staining (in hsematoxylin and 
eosin preparations) matter, of a membranous or connective 
tissue-like appearance, is seen on the surface ; sometimes the 
membrane is of linear tenuity, sometimes more bulky. 
Where the muscle strands leave the mass a few chromophil 
cells appear sometimes to have travelled a little way along 
the strand, and hence are seen adhering to the strand just 
after it has emerged from the main aggregate of the cells. 
While some such cells appear to be underneath the peritoneal 
investment of the strand, others are absolutely continuous 
with it ; in other words, some of the peritoneal cells, instead 
of retaining the usual flattened form, are swollen, and contain 
the chromophil substance. 
Pheretima of diameter 1 mm. — In a still younger 
stage the cells, which already have a very marked chromophil 
