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The Musculature. 



The transverse and longitudinal muscles between the cuticula and 

 subcuticula have already been mentioned, and it has already been stated 

 that I consider the subcuticula itself to belong to the contractile elements. 



The longitudinal, transverse, and dorsoventral systems of muscles 

 (Parenclvym muskeln, Braun) are found in characteristic arrangement 

 in the strobila. The longitudinal muscles are the most developed of the 

 three systems. They lie in a single layer between the subcuticula and 

 the transverse muscles, being divided into rather indistinct bundles by 

 the dorsoventral muscles. The longitudinal muscle layer is broken laterally 

 on both sides. 



The fibres run continuously, through more than one segment, parallel 

 with each other. They are roundish on transverse sections, often enclos- 

 ing a hollow, appearing then annuliform. Myoblasts are fairly frequent. 



The transverse muscles form a much weaker layer than the longi- 

 tudinal, consisting both of fewer and of thinner fibres. The dorsal and 

 ventral plates of transverse fibres meet laterally, but the fibres of either 

 plate do not pass round into the other plate. Myoblasts are frequent. 



The dorsoventral is the weakest system, being composed of single 

 fibres ; the fibres are thickest in the lateral fields. The fibres of this 

 system appear to attach to the fibrillae already mentioned as continuing 

 the subcuticular cells. Myoblasts are very frequent. 



The musculature of the scolex is more complicated, but consists of 

 fibres derived from these three systems. At the base of the scolex the 

 longitudinal fibres of dorsal and ventral series approach so close as almost 

 to meet laterally. 



The transverse muscles form a much thicker and denser layer, and 

 the dorsoventral muscles become more prominent and more frequent. 

 Entering the scolex their arrangement and direction beconaes changed, 

 owing to the other organs contained in the scolex. Without going into 

 detail, the following systems of muscles can be mentioned as occurring in 

 the scolex : — 



(1) A diagonal cross system anterior to the terminal loops of the 



longitudinal canals ; it covers the entire anterior surface of the 

 scolex, passing from the front of the left ventral to the right 

 dorsal, and from the right ventral to the left dorsal sucker. 



(2) A second diagonal cross system composed of four bundles, each 



consisting of a few fibres ; it is situated just behind the ter- 

 minal loops of the longitudinal canals and runs from sucker to 

 sucker in such a way that (1) fibres from the lateral face of 

 the right ventral sucker run to the lateral face of the left dorsal 

 sucker; (2) fibres from the lateral face of the right ventral 

 sucker run to the median face of the left dorsal sucker ; (3) 

 fibres from the median face of the left ventral sucker run to the 



