264 The Microscope. 



the muscular fibers in the heart of adult and fcetal vertebrates (see 

 Weismann and Gage), it is seen that the differences between 

 skeletal and cardiac muscle are not so radical as usually supposed. 

 The fact that anastomoses occur between fibers points to the 

 conclusion that the physiological connection may also be as 

 intimate as the morphological, and gives rise to the query whether 

 each of the fibers so united has a separate connection with a nerve. 



EXPLANATION OF THE PLATES. 



PLATE XI. 



Magnification of Figs. 35-44, 260 diameters; of Fig. 45, about 

 50 diameters. 



Fig. 35. — A tapering intramuscular end i, closely adherent to 

 the surface of a fiber of full size. From the brachium of a young 

 English sparrow. 



Fig. 30. — A tapering and branched intramuscular end i, closely 

 attached to the side of a fiber at its full size. From the shoulder 

 of a house mouse. 



37. — Two tapering and branched intramuscular ends, belong- 

 ing to fibers extending in the same direction, adherent to each 

 other, one terminating .2 mm. from the tip of the other. From the 

 biceps femoris of a house mouse. 



Fig. 38. — Two tajDering and branched intramuscular ends, 

 belonging to fibers extending from opposite tendons, adherent to 

 each other and lapping for about .2 mm. From the 2^^cf oralis of a 

 house mouse. 



Fig. 39. — The thick tapering ends of two fibers from opposite 

 tendons. They are closely connected at mm. The line of union is 

 zigzag, as though the fine processes such as seen at I interdigitate. 

 At bb the fibers are of full size. From near the middle of the 

 biceps femoris of a house mouse. 



Fig. 40. — An anastomosis of two fibers, in the connecting 

 branches of which are seen a number of longitudinal clefts. The 

 smaller fiber x comes to an end at this point, and in the specimen 

 can be traced for some distance toward the tendon. The larger 

 fiber has its maximum size at b, and from h it can be traced 4 mm. 

 to its tapering, branched, intramuscular end, one of the branches 

 forming an anastomosis with another fiber. From the biceps 

 femoris of a house mouse. 



Fig. 41. — An anastomosis of two fibers by a number of 

 branches from the tip of one of them. The smaller fiber x in the 



For general considerations, see PI. VIII-X. 



