490 JOSEPH STAFFORD, 



two fibres run together for a piece an then separate giving this ap- 

 pearance. Also it is sometimes possible to follow the one muscle 

 past the other on both sides. But after considering these cases and 

 also after taking into account the thicknesses of the main and the 

 ])ranch fibres I feel quite sure that there are real branchings. 



In sections, of course, the horizontal are the only ones that for 

 This purpose are ot value and of them it is only possible on account 

 of the curving form of the septum to get small surfaces visible at 

 once. Once I had an exceedingly good preparation of the living 

 animal with the ventral disk cut away. In this the large septal 

 muscles stoot out so distinctly from all others as to surprise me when 

 I came upon them. They put me in mind of serpents , distended, 

 coiled over each other, bent, or intertwined so as to defy my following 

 their course. At that time I did not know enough to look for 

 branchings, and trials to get as favorable a preparation, in the same 

 way, have failed. On some of these fibres I have found myoblasts. 

 The transverse fibres are far smaller and generally so closely 

 packed together as to form a membrane. They do not run entirely 

 parallel, some crossing at a small angle. At the posterior end of the 

 septum its fibres disperse along the walls of the parenchyma cells. 



The diaphragma functions as a huge muscle that can work in 

 either a longitudinal or a transverse direction, and also serves to 

 support the heavy copulatory organs, vitellaria, and intestine, and to 

 give insertion to many parenchyma-muscles both dorsal and ventral 

 to it. The importance of this organ, stretching through the centre 

 of the body, as a means of locomotion, and especially of locomotion 

 under difficulties of considerable pressure, will be evident. 



Parenchyma muscles. Dorso-ventral parenchyma muscles 

 are particularly apparent at the sides of the anterior end of the 

 pharynx. From this point backwards to the genital orifice they are 

 well developed but more posteriorly they are much thinner and more 

 wrested from this direction by the interposition of genital organs. In 

 the infra-septal parenchyma, i. e. in that portion of the body or of 

 the foot which lies more anteriorly between septum and ventral disk, 

 are to be found also extremely thick fibres whose direction is mainly 

 from the septum to the sucker. From the line along which septum 

 and body walls meet are seen, in transverse sections, muscles extend- 

 ing ventralwards, splitting at their ends and inserting into the mem- 

 brane above the ventral sucker. These do not all lie in the same 

 plane but spread to the two rows of alveoli of the sucker belonging 



