TO THE ELEMENTAET EIBEBS OE STEIPED MUSCLE. 
909. 
Fig. 15. Dmsion of dark-bordered fibre with fine fibres ramifying in the. sheath of 
the nerve. From the pectoral muscle, x 7 00. 
PLATE XLIII. 
Distribution of finest dark-bordered fibres on the surface of a muscular fibre 
fi’om the pectoral muscle. At the edge of the specimen on the left, the deli- 
cate nerve-fibres are seen lying, not only upon the external surface of the sar- 
colemma, but at an appreciable distance from the outer surface. X 700. 
Division of dark-bordered fibre and formation of fine networks. Pectoral 
muscle of the frog. x700. 
Very fine nerve-fibres on the surface of the muscular fibre. From the pectoral 
of a young frog. Several of these fibres can be followed to the edge of the 
muscular fibre, where they are lost. X 1700. 
Fine fibres from the sheath of the nerve, di\dding and subdividing on the surface 
of two elementary muscular fibres. From muscle of the neck of the frog. 
x700 diameters. Compare the appearance of the fibres represented at 5, h 
in the drawing, with fibres h in figs. 16, 15, 14, & 20, which undoubtedly 
come from true dark-bordered nerve-fibres. 
Division of dark-bordered fibre on surface of muscular fibre. 
Fine dark-bordered fibre, and fibres in sheath of the nerve, Avith nuclei. From 
muscle of the neck of the fr’og. X 700. 
Fine fibres residting fr-om the subdivision of a dark-bordered fibre ramifying on 
a muscular fibre. Pectoral muscle. X 700. 
Dmsion of dark-bordered fibres crossing a muscular fibre. 
PLATE XLIV. 
Fig. 24. Dark-bordered fibre and fine fibre in the sheath ruptured. From muscle of 
under jaw of frog, x 700. 
Fig. 25. Dark-bordered fibre and fine fibres, showing fibres crossing each other and 
forming very fine branches composed of several finer fibres. X 700. 
Fig. 26. Dark-bordered fibres and fine fibres in sheath between muscular fibres of the 
pectoral muscle of the fr’og. x 700. 
Fig. 27. Dark-bordered fibre, with fine fibres external to it, ramifying between the ele- 
mentary muscular fibres of the pectoral muscle of the frog, x 700. 
Fig. 28. Branching and division of dark-bordered nerve-fibre near terminal branches, and 
bundles of fine fibres. Several nuclei are seen in connexion with both sets of 
fibres. From the bladder of the frog. At a the dark-bordered fibre becomes 
resolved into several fine fibres. x700. 
Fig. 29. Fine fibres continued from a dark-bordered fibre, and the fibres in itsj^sheath 
crossing a young muscular fibre, x 700. 
Fig. 30. Young muscular fibre from the pectoral muscle of the frog, near one of the 
Fig. 16. 
Fig. 17. 
Fig. 18. 
Fig. 19. 
Fig. 20. 
Fig. 21. 
Fig. 22. 
Fig. 23. 
