658 DAVID HILT TENNENT. 
Sus-Curicu.a. 
Immediately below the cuticle lies a homogeneous layer of 
more deeply staining material in which the muscles are 
imbedded. ‘This may be regarded as the sub-cuticular layer. 
MUSCULATURE. 
The body musculature consists of both ring and longi- 
tudinal muscle fibres, the former lying closely applied to the 
lower surface of the cuticle, the latter lying just beneath the 
ring muscles. In transverse sections the longitudinal muscles 
appear as a row of fine dots. In longitudinal sections the 
ring muscles have a similar appearance. 
THe Bopy PARENCHYMA. 
The organs of the body lie embedded in parenchymatous 
tissue. The nucleiare prominent and stain readily, while cell 
boundaries and cytoplasm are difficult to demonstrate. The 
gland cells, of which mention has already been made, lie 
closely surrounded by the parenchymatous cells. 
Tue Cystogenous ORGAN. 
In the anterior end of the body, immediately behind the 
three-lipped invagination, lies a pear-shaped complex of gland 
cells and parenchyma nuclei. This is the “ mundnapf” of 
the German investigators. During contractions of the body 
it is shifted backwards and forwards, and its walls contracted 
by means of the layers of diagonal muscle fibres lying in its 
limiting wall (figs. 41 and 43, mc.). 
In the oldest specimens of Bucephalus which I obtained, 
a slight pressure forced out a rounded plug of transparent, 
viscid material (fig. 23). This complex of glands, I believe, 
produces the material from which the cyst is formed. 
