ACTIVITIES OF THE AMAROUCIUM TADPOLE 



243 



was noted and figured by Kowalevsky^ and Seeliger, the muscle 

 fibrillae take a slightly oblique course in each cell and the fibrillae 

 of adjacent muscle cells seem to be continuous from cell to cell. 

 When a tadpole is lightly held between a slide and cover-slip, 

 the vibrations of the tail cause the body to oscillate, the anterior 

 end seeming to move in a circular or oval path on a pivot located 

 near the posterior part of the body. When a part of the tail is 

 amputated, the vibrations of the remaining stump do not pro- 



Fig. 2 Camera outline drawing of a muscle cell, showing the oblique position 

 of the fibrillae in the cortical layer, the continuation of the fibrillae from cell to 

 cell, and the cross striations in one fibrilla. 



ABBREVIATIOIJS (fIG. 1) 



as, atrial siphon 



dap, dorsal adhesive papilla 



L, left side 



Ipo, light-perceiving organ 



map, middle adhesive papilla 



mc, muscle-cell sheath 



n, notocord 



OS, oral siphon 



R, right side 



sc, statolith cell 



sv, sensory vesicle 



if, tail fin 



tg, groove in test resulting from pres- 

 sure of the tail during embryonic 

 development 



tv, test vesicles 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 30, NO. 2 



