230 The Microscope. 



general form and relations of the striated muscular fibers could not 

 be made. In the skin the connective tissue does not yield to 

 reagents until the fibers are too much softened to be dissected well, 

 and in the tongue and oesophagus the fibers are interlaced in such a 

 way as to make it difficult either to dissect them out or to trace 

 them under the microscope in their natural relations. In the skin 

 of the ear of the mouse, however, the circumstances are more favor- 

 able, and it was found that there are only cylindrical fibers which 

 are very short |^ to 2 or 3 mm. In situ these are seen to be arranged 

 in small bundles and the bundles are placed at a variety of angles 

 with each other. In the long skin muscle of the back no cylindrical 

 fibers could be traced in either the bat or the mouse. A few taper- 

 ing fibers and one fusiform fiber (6 mm.) were found in the mouse . 



Of the large number of fine tapering ends found in the skin 

 muscles of the back it was often impossible to determine whether 

 they were intramuscular or terminated in the corium. A few were 

 found in situ part of these being closely attached to other fibers and 

 part ending in the corium. 



In the tongue of the mouse and bat there are groups of parallel 

 fibers, the terminations of which are at about the same level and 

 apparently in the corium. Their relative position is shown in Figs. 

 28 to 30. The ends are usually wider than the body of the fiber 

 (Fig. 28). A few shoi't fibers, about 2 mm., were isolated from the 

 tongue of the mouse, each of which had two such endings. 



In the oesophagus of the mouse and bat two layers of striated 

 fibers were found which extend to, but not upon, the stomach. In 

 the centimeter next the stomach there were also numerous un- 

 striated fibers. A few short, striated fibers, about 2 or 3 mm., were 

 isolated. They taper somewhat toward the end but generally at the 

 end again spread out (Fig. 24). 



In these positions the fibers have a much smaller average 

 diameter than in the limb and trunk muscles, being about one-half 

 as large. 



7. Types of Intramuscular Ends. — Rollett (1856) first de- 

 scribed and figured intramuscular ends of a simple tapering form . 

 In all the animals considered in this paper, such ends were found in 

 many of the skeletal muscles having tapering fibers (Figs. 2 and 4) . 

 They are found occasionally in the mouse and shrew, frequently in 

 the bat and are the predominant fonn in the English sparrow. 



Biesiadecki and Herzig (1858) showed that in the horse, frog 

 and Lota vulgaris are found dichotomously divided ends within the 



