The Microscope. 235 



Fig. 7. — A tapering fiber from the skin of the back of a house 

 mouse. In the skin of the mouse this is not an unusual form of 

 fiber, tholigh the branches at i are generally shorter. 



Fig. 8. — A tapering fiber from the obliquus abdominis of a 

 house mouse. The branches are nearly at right angles with the 

 intramuscular end, ^, a condition not frequently seen in a free end. 

 The whole fiber is small, being only about 18/^ 6 mm. from the 

 intramuscular end. 



Fig. 9. — A fusiform fiber 7 mm. long from the vastus externus, a 

 muscle 16 mm. long, of the house mouse. The two ends, i i, are both 

 intramuscular and branched; the part h is 2 min. from an end and is 

 also branched. Dissociated in caustic potash. 



Fig. 10. — Part of a tapering fiber from the vastus externus of a 

 young English sparrow. The intramuscular end, i, is much branched, 

 a form not common in the sparrow. The fiber has a gradual taper 

 of 2 mm. to 6, the body of the fibei*. 



Fig. 11. — The intramuscular end of a fiber from the vastus 

 externus of a young English sparrow. It has a number of un- 

 striated, bud-like processes. For 6 mm. from this point the fiber 

 increases only slightly in diameter. 



Fig. 12. — A tapering fiber from the vastus externus of the 

 house mouse. i, The intramuscular end has many striated 

 branches occurring from the third to the fifth tenth of a millimeter 

 from the tip; the last ^^ mm. of the fiber is of a simple tapering 

 form. The ends of the branches show plainly the same fringed 

 appearance noted in the tendinous end of Fig. 4. This type of 

 endings is frequent in the mouse and shrew. At h, 3 mm. from the 

 end, the fiber is about two-thirds its full size. 



PLATE IX. 



Magnification, 260 diameters. 



Fig. 13. A tapering fiber, 10 mm. long, from the latissimus, a 

 muscle 27 mm. long, of an adult field mouse. The intramuscular 

 end, i, has several branches seen both at the side and on the surface 

 of the fiber; branches continue to be given off from the fiber until it 

 is of full size at b, which is 3 mm. from i. 



Fig. 14. — An intramuscular branched end of a fiber from the 

 pectoralis of a shrew. 



Fig. 15. — An intramuscular branched end of a fiber from the 

 pectoralis of a shrew. Branches are given ofP at intervals for j*^ mm. 



Fig. 16. — An intramuscular branched end from the latissimus 

 of a gray bat. Branched ends are given off at intervals for ^^ mm . 



