380 
Tetrm'hynclius erinaceus 
inserted into the integument of the suctorial faces of the bothridia on each 
side of the shallow fossae which run longitudinally along the faces of the 
latter organs. 
c. Transverse fibres running chiefly dorso-ventrally in the parts of 
the scolex external to the proboscides. They form two compact sheets 
of fibres in the axial parts of the scolex but fan out in the bothridia so 
that their fibres are inserted in the tissues beneath the integument of 
the suctorial faces between the longitudinal fossae and the lateral 
margins. 
d. Tangential fibres which are gathered up into two compact 
sheets in the central parts of the scolex, and which run roughly 
parallel to the central parts of the suctorial faces of the bothridia. 
Laterally these fibres radiate out and are inserted into the integument 
of the external convex faces of the bothridia. 
f. Fibres inserted in the marginal parts of the suctorial faces of 
the bothridia. Some of these run dorso-ventrally from one bothridium 
to the other, and are thus identical with series c but others originate in 
the dense tissue where the bothridium arises from the axial parts of 
the scolex. 
g. Radial fibres running in sheets parallel to the marginal parts of 
the bothridia and inserted into the tissues forming the rims of the latter. 
Some of these fibres originate in the dense tissue at the bases of the 
bothridia, but others are identical with the fibres of series a and c. 
h. Numerous fibres which join the suctorial (concave) and external 
(convex) faces of the bothridia. They may function in flattening the 
latter organs. 
e. In addition to all these fibres there are others which run 
longitudinally beneath the integument both in the bothridia and in the 
axial part of the scolex. Those which are present in the bothridia are 
evidently inserted into the dense tissue at the anterior and posterior 
ends of these organs, but those present in the axial part of the scolex 
are an integral part of the general longitudinal series of integumentary 
muscles of the whole strobila. 
All these muscles fibres are smooth and unstriated and are not 
provided with nuclei nor have they any myoblast substance. They are 
about 2 /A in diameter, stain deeply with methyl-blue-eosin and can 
easily be distinguished from the surrounding tissues. 
The Muscles of the Proboscis. The extrusion of the proboscis is not 
directly a muscular act. The lumina of the sheaths and bulbs are filled 
with fluid and the extrusion of the proboscides is the result of an increase 
