200 Egbert Thompson Young, 



and extended. A sarcolemma, such as Pintner (1881) and Vaulle- 

 GARD (1895) have described in the Tetrarhynchidae and Keaemer 

 (1892) in Taenia filicollis and torulosa, may be explained as a sheath 

 of parenchyma fibres which follow the muscles and surround them 

 more or less intimately. The diiferentiation of the muscles into 

 cortex and medulla has been described by various authors; notably 

 Leuckart (1879 — 86) ; Nitsche (1873) in Ligula and Taenia uncMata, 

 Salensky (1874) in Amphilina, Schieeeerdeckee (1874) in Taenia 

 solium and cucumerina, and Zernecke (1895) in Ligula. Evidently 

 basing his text on the work of these authors, Schneider (1902) 

 describes this as the typical muscle structure in Cestodes. The 

 branching- character of the muscles was described by Salensky (1874) 

 for the transverse and longitudinal muscles of Amphilina, yet Braun 

 (1894—1900, p. 1351) says ". . . nur von den Dorsoventralfasern . . . 

 ist es bekannt, daß die Enden sich verästeln . . ." Lately, Eössler 

 (1902) has described the branching character of the transverse 

 muscles in the bladder wall of Cysticercus. 



The present study of Cysticercus pisiformis and Taenia 

 serrata ^) leads to the following conception of the structure of its 

 musculature : The muscles consist of bundles of very fine fibrillae in 

 intimate contact with each other, which have been derived originally 

 from the parenchyma. These muscles frequently branch into larger 

 or smaller bundles of fibrillae. Anastomoses are common. In con- 

 nection with the muscles are neuro-muscular cells, their fibrillae 

 probably in direct protoplasmic continuity with those of the muscles 

 themselves. No differentiation into cortex and medulla occurs, the 

 occasionally the muscle fibrillae may be so arranged as to form a 

 hollow core at the center of the muscle, which, however is apparently 

 empty. -) The shape of the muscles varies depending on their state 

 of contraction. Sometimes they present parallel walls, at other 

 times they are spindle-shaped. Frequently alternating zones of 

 thicker and thinner parts occur. 



1) From the occasional observations made on Dipylklium caninum, 

 the structure of its muscles is apparently the same as that of the above 

 named forms. 



2) This may be an abnormality due to shrinkage. 



