SEA-FISHERIES LABORATORY. 



89 



The presence of this complex myzorhynchus, and the 

 variability of the shapes into which it may be thrown by 

 the action of its muscles, often renders the identification of 

 species of Echeneibothrium a difficult matter. It often 

 happens that the terminal os cannot be seen, that the 



Proboscis 



Re.tr a dorm us da s 

 Of the proboscis 



Pig. 7. Echeneibothrium variabile, van Beneclen. 

 Section through myzorhynchus. Mag. 110 dia. 



myzorhynchus is large, and flattened out in the transverse 

 plane, while the bothridia and their pedicels may be very 

 much contracted. These changes are without doubt caused 

 by the eversion of the internal proboscidal sucker, and the 

 reversal of the surfaces of the latter. Then the retractor 

 muscles, pulling on the walls of the proboscis, throw the 

 latter into lobe-shaped structures. This radial structure 

 can often be seen when looking down on the surface of the 

 myzorhynchus; it is shown, for instance, in fig. 4, p. 85, 



