1914] A New Cestode from Amia Calva L. 89 



for the movements of the auricles alone. From their arrangement they 

 doubtless serve, in conjunction with other fibres to be described below, 

 to extend the appendages away from the body as the leaf-like structures 

 mentioned above. 



The dorso-ventral or sagittal muscles are divided 

 into six groups by the three excretory vessels and the two nerve strands 

 which in the foremost joints occupy most of the medulla and are situated 

 so close together in many sections that only individual fibres appear 

 between them. The fibres themselves are more numerous, like the 

 coronal muscles, anterior to the junction of two proglottides where the 

 four most lateral groups, i.e., those between the nerve strands and 

 the lateral vessels and those outside of the nerve strands pass from auricle 

 to auricle on each side of the worm (Fig. 35). In the forward end 

 of the joint more fibres are situated between the vessels and fewer 

 laterally. The middle lot could not be traced beyond the subcuticula, 

 while the lateral groups, on the other hand, can be easily followed to the 

 cuticula of the auricular ring and appendages, in which latter they, along 

 with the coronal fibres mentioned above, constitute the transversely 

 radiating group. Farther back they dwindle down gradually until in 

 gravid proglottides only a few coiled fibres appear between the testes 

 and vitelline follicles or alongside the cirrus-pouch and uterine-cavity. 

 The individual fibre closely resembles that of the coronal series, shown 

 in Fig. 9a, excepting that it is shorter. 



The longitudinal muscles of the parenchyma are divisible 

 into two series, an inner and an outer, of which the latter appears only 

 in the anterior end of the strobila. In transverse sections through the 

 middle of the foremost joints they are arranged in small groups, with no 

 constant number of fibres in each, in two concavo-convex bands between 

 the medullary and cortical parenchyma, that is, about half way from the 

 centre of the section to the periphery excepting laterally where they are 

 situated relatively farther out. Here the thin edges come together 

 immediately outside of the nerve strands. Throughout their course 

 transversely they are penetrated by the sagittal muscles. As one nears 

 the very short region between successive proglottides, in following 

 through a transverse series, some of the fibres (more correctly fibrils, 

 from, the above view of the constitution of the fibre) decrease in diameter 

 and number, especially laterally, and become more loosely arranged, as 

 they diverge from one another. Immediately ahead or behind, as the 

 case may be, they again appear as above. On the other hand a great 

 many pass from joint to joint uninterrupted. From this fraying out of 

 the fibres between successive joints it was concluded that the lengths of 

 some of them, at least, did not exceed that of the proglottis : in the mature, 



