320 DR. H. LYSTER JAMESON ON 
of the muscular insertions or singly in the non-muscular parts of 
the body-wall and mantle. 
Text-fig. 40. 



“ = if DE : 
Bs 
A. The irregular columnar and amorphous substances, shown at col. in text-figure 39. 
nac., nacreous lining of the shell; nae.’, nacre deposited shortly after intro- 
duction of nucleus, passing over into the repair-substance (¢r.) ; nae.’’, nacre 
continuous with the layers investing the nucleus; col., col.’, columnar repair- 
substance; am., amorphous repair-substance. X 35. 
BR. The fan-shaped mass of repair-substance, shown at col.’ in text-figure 39. 
nu., the introduced “nucleus”’; nac., the original nacreous lining of the 
shell; nac.’, the first layers of nacre, separated after the introduction of the 
nucleus; cpl., columnar repair-substance; am., amorphous repair-substance ; 
gr., granular matter, perhaps of extraneous origin. > 100. 
[62] 
