106 0. F. MARSHALL. 



DESCRIPTION OF PLATE VI, 



Illustrating Mr. C. F. Marshall's paper on " Observations on 

 the Structure and Distribution of Striped and Unstriped 

 Muscle in the Animal Kingdom, and a Theory of Muscular 

 Contraction." 



[la all cases the gold chloride used was 1 per cent., the formic acid 

 25 per cent. The " usual gold method," when stated, means : 1 per cent, 

 acetic acid for a few seconds, gold chloride thirty minutes, formic acid twenty- 

 four hours in the dark.] 



Fig. 1. — Ectoderm cell of Hydra : gold preparation. (1 per cent, acetic 

 acid for a few seconds, gold chloride thirty minutes, formic acid one hour, 

 exposed to sun.) «. Intracellular network, b. Muscular process, c. Intra- 

 nuclear network. ^ immersion obj. 



Fig. 2. — Portion of muscular fibre of Medusa. Usual gold method. 

 J^ imm. obj. 



Fig. 3. — Portion of muscle-cell of Earthworm, showing longitudinal rows 

 of dots. Usual gold method. -^ imm. obj. 



Fig. 4. — Muscle-fibre from adductor of Pecten, showing network. Usual 

 gold method, y^ imm. obj. 



Fig. 5. — Muscle-fibre from heart of Patella. (Acetic acid, 5 per cent., 

 two minutes, gold thirty minutes, formic acid two hours, at 40° C.) Zeiss, 

 J obj. 



Fig. 6. — Crayfish heart, Gold preparation of. (Acetic acid, 5 per cent., a 

 few seconds, gold twenty minutes, formic acid one hour, at 40° C.) £ obj. 



Fig. 7. — Muscle-fibre of Daphnia. (Acetic acid, 5 per cent., ten minutes, 

 gold thirty minutes, formic acid two hours, at 40° C.) -^ imm. obj. 



Fig. 8. — Muscle of Bird (left in formic acid three days). ^ imm. obj. 



Fig. 9. — Muscle-cell from Rat's heart, showing network. Usual gold 

 method. Zeiss, D obj. 



Fig. 10. — Muscle-fibre from Frog's heart. (Osmic acid, 1 per cent., half an 

 bour.) ^ imm. obj. 



Fig. 11. — Network from heart muscle of Bird. (5 per cent, acetic acid 

 fifteen minutes, gold thirty minutes, formic acid twenty-four hours.) ^ 

 imm. obj. 



Fig. 12. — Portion of unstriped muscle-cell from mesentery of newt, show- 



