Fig 13.

(A) Tracings of longitudinal sections through the equatorial regions of bag₂ fibre from spindles 4, 5 and 10 (from Banks, 1986). Profiles of primary-ending terminals are shown in blue; equatorial nuclei are shown in outline, some with nucleoli visible as black dots. Sarcomere lengths are the means of 50 sarcomeres proximal and distal to the sensory endings for each bag₂ fibre. (B) Method of obtaining the data in Table2 from the tracings in (A). I, radius of circle fitting the curvature of the inner membrane of a sensory-terminal profile; O, radius of circle fitting the curvature of the outer membrane of a sensory-terminal profile; C, half the length of the common chord of I and O.