DR. MARTIN BARRY ON FIBRE. 123 



Fig. 40. More advanced state of apparently corresponding objects ; the fila- 

 ments enlarged. 



Fig. 41. a. The points of contact in the spiral threads, which constitute the 

 filament, beginning to separate. /3. This separation more complete 

 (par. 27). 



Fig. 42. Appearances, in three instances, of the nuclei in muscle-tube. The 

 dots show merely the breadth of these tubes. We have here evidence 

 of division (a) and subdivision ((3) of the nucleus, with a diminution 

 in its size (par. 42). Filaments were very distinct in the tube (3. 

 Fig. 43. Sketch showing some displacement of filaments by the nucleus ; and 

 slight enlargement at this part in the breadth of the tube. It is the 

 edges of the filaments that are seen in this figure. 



Fig. 44. a. Nuclei and spirals contained in a tube. /3. Another part of the same 

 tube : its diameter greater ; and this part filled with discs, the ar- 

 rangement of which was regular (pars. 22, 42). These discs quite red, 

 and resembling young blood-corpuscles (par. 42). 



Fig. 45. Chick in ovo ; incubated twelve (?) days. Outline of the extremity of a 

 muscle-tube, and its contents. These were discs, having precisely the 

 same appearance as young blood-corpuscles (par. 42) ; and they were 

 arranged with great regularity (pars. 22, 42) in the tube (see the explana- 

 tion of fig. 48). 



Fig. 46. Tadpole, 5^'". From the tail. Muscle-tube containing discs having the 

 same appearance as young blood-corpuscles (par. 42), each of which ex- 

 hibited bright points near the centre, these denoting the situations of 

 future discs (par. 44). 



Fig. 47. Turtle. Muscle-tube from the heart. The tube contains rings linked toge- 

 ther, and preparing to form interlaced spirals (pars. 22, 42). 



Fig. 48. Tadpole, 5^'". Muscle-tube. From the tail. a. Rings, arranged with great 

 regularity in the same way as the discs in figs. 45 and 46. /3. Structure of 

 the rings, y. Spirals formed out of such rings (pars. 22, 42). I. Structure 

 of the spirals. Each ring appeared to contain the elements of future 

 rings (par. 44), not represented in the figure. 

 Fig. 49. Tadpole, 5^'". Muscle-tube, in which are seen interlacing spirals, each of 



which surrounded minuter objects (filaments ?). 



Fig. 50. Tadpole, about 5"'. Muscle-filament ("Jibrir) on its flat surface. It mea- 

 sured in breadth y^oo'" (P ai> - 45 )- 

 Fig. 51. Young Monoculus. Flat surface of a muscle-filament (" fibril"), observed 



in the leg, near its extremity (par. 45). 



Fig. 52. Turtle. From the heart. Muscle-filament (' fibril") on its flat surface 

 (par. 45). At the lower part the two spiral threads composing it have 

 become unconnected. One of these threads still presents the spiral form. 



R2 



