350 LEWIS hl:nkv gough, 



ing the connection of the whole row to a muscle. The 

 fibrilUe of the outermost m^'ohlasts do not insert directly in, 

 the cuticula, but ai'e in contact with the fibrilhe arising from 

 the subcuticular cells. 



Cells similar to these simplest myoblasts have been 

 seen and described by Schiefferdeckei- (1874) in Ta3nia 

 sagiuata, Kiichentn.; he considered them to be connective 

 elements; and by Hamaun in Taenia (Mesocestoides) 

 lineata, Hud., who described them as elements of the 

 paienchynui. 



(2) Bipolar myoblasts with lateral fib rill ;v are, in 

 Avitellina, chiefly found in the transverse muscle. They 

 are the form of myobhist most frequently recorded by recent 

 authors (e. g. Pinter, 1881; Hamann, 1882; Kriiiner, 1892; 

 Will, 1893; Zernecke, 1895; Rossler, 1902; Young, 1908) 

 in various genera and species. These muscle-cells differ from 

 those described above inasmuch as the fibrilla runs con- 

 tinuously over one surface of the cell and does not originate 

 only at the poles, otherwise they are very similar in appearance 

 and dimensions (figs. 24, 25). Their nuclei measure 3*5 // x 

 4*25 /t; their plasma is attached to the fibrilla, being widest 

 at the middle and drawn out to a point at each pole. The 

 plasma stains fairly deeply, and has a very distinct outline, 

 probably being enclosed by a membrane. The fibrilla? are 

 long, apparently homogeneous, and lie arranged parallel to 

 each other. At the margins the fibrillse of the transverse 

 muscle spread fan-like towards the cuticula, as usual in other 

 cestodes. Some of them appear to connect with the most 

 lateral subcuticular cells. The fibrilhe are very thin, less 

 than 1 n in diameter. Young (1908), describing such myo- 

 blasts, states that the myoblast is alwa3's connected to the 

 muscle by fibrillte, even when the cell remains very close to 

 the muscle. I liave not been able to verify this observation 

 in my material. 



(o) The elongate Iji polar myoblasts, lying ax ially 

 in tlie tubiform muscles of the longitudinal muscles, ai-e 

 more difficult to observe than the other two varieties of 



