STRUCTURE OF THE CYSTICERCUS CELLULOSE. 
95 
Development of the Cysticercus cellulosae. 
The earliest appearance of the incipient stage of the 
Cysticercus celluloses is a fusiform collection of small cells and 
molecules in the substance of a primary muscular fasciculus, 
or immediately beneath its sarcolemma. These cells, in this 
condition of the entozoon, have only an imperfect or partial 
covering; however, they soon become completely enclosed in 
a well-defined membrane, which is at first homogeneous, but 
which afterwards sends out short, slender, projecting fibres, 
resembling short hairs or cilia. These hair-like fibres, 
though resembling in some respects cilia, differ from them in 
being much less sharply defined and less pointed ; however, 
for convenience sake, l shall speak of them as cilia. Their 
direction is remarkable. At either extremity of the fusiform 
animal they are reflected backwards at a very acute angle, 
like the barbs of a feather, their direction being of course 
opposite at the two ends. They become less and less in- 
clined as they approach the middle of the body, where they 
stand out at right angles to the surface. The apparatus of 
cilia-like processes above described is evidently designed to 
give to the entozoon, whilst in this stage of its existence, the 
power of penetrating between the ultimate muscular fibrillae, 
and thus to enable it to force its way from the interior of a 
primary fasciculus into the spaces between the muscular 
fibres. This will be the effect of the friction of the fibrillae 
against the cilia, which will allow T of motion in one direction 
only. And as its two ends must move in opposite directions, 
the cilia will also serve to aid the entozoon in its development 
longitudinally. That such is their office will be apparent on 
examining a sufficient number of specimens; in some of 
which the primary fasciculi w T ill be seen to have been com- 
pletely split up by these animals. But the correctness of 
this inference is more strikingly proved by the influence 
which the size and arrangement of the primary bundles of 
muscular fibres have upon the form and dimensions of the 
entozoa. Thus in the muscular parietes of the heart, where 
the primary fasciculi are smaller, and, from their frequent 
interlacing, shorter than in other parts, the Cysticerci are, in 
this stage of their development, also very short and of a dif- 
ferent form to those found in other muscles, composed of 
striped fibre, although in other respects perfectly similar ; 
and, when completely formed, those taken from the heart 
cannot be distinguished from those formed in other muscles. 
The cells which have been alluded to as forming the prin,- 
