J. Johnstone 
379 
The Bothridia Muscles. PI. XIX, fig. 4 represents a transverse 
section through the anterior part of the scolex. The bothridia are seen 
to be two shallow suckers, the marginal parts of which are composed of 
dense parenchyma and muscle fibres. The central parts are mainly 
parenchymatous but contain also some muscle fibres with other tissues. 
Towards the lateral margins, and placed symmetrically with regard to 
each other, are the proboscis sheaths. The pr-oboscides themselves 
are evaginated and the structures within the sheaths are the retractor 
muscles. 
It is difficult to represent the exact dispositions of all the systems 
of muscle fibres in such a figure as this so I have prepared a diagram 
which shows the various components of the musculature of the bothridia 
as they would be seen if projected in a single transverse plane. They 
form a group of mutually antagonistic muscles the action of which 
permits of a great variety of movements on the part of the bothridia. 
They may be arranged as follows, the lettering of the various paragraphs 
corresponding to that of the diagram. 
Fig. 3. Diagrammatic transverse section of the scolex representing the arrangement 
of the muscle fibres. Only a few fibres of each series are figured. 
a. Transverse fibres running straight across from side to side of 
the scolex in two parallel bundles, one of which is internal to each 
dorsal and ventral pair of proboscides. They are inserted into the dense 
parenchymatous tissue at the places of origin of the bothridia. 
h. Transverse dorso-ventral fibres which run at right angles to 
those lettered a, and which are arranged in two bundles or sheets, one 
of w’hich is internal to each lateral pair of proboscides. They are 
25—2 
V 
