ABNORMALITIES IN CESTODE MONIEZIA. I(X) 



number of facts which possibly indicate a close relation between 

 the appearance and early development of the proglottids and the 

 nervous system. The figures of whole mounts (Figs. 4752) 

 and of transverse and longitudinal sections through the neck 

 region (Figs. 42, 43, 45) show that the earliest aggregations of 

 the parenchyma-nuclei occur in the region in which the lateral 

 longitudinal nerve-cords lie, and that growth of the proglottids fol- 

 lows the lines which the transverse dorsal and ventral commis- 

 sures must take as they develop. 



In the transverse section, Fig. 43, the nuclei of the central 

 parenchyma are mostly situated in an indistinct ring around the 

 outer margin of the central parenchyma. In Fig. 42, from a 

 more anterior region, this arrangement is less clearly marked. 

 In the longitudinal sagittal section near the median plane (Fig. 

 45), which is taken from a region posterior to Fig. 43, the same 

 arrangement, or more rapid multiplication of the nuclei is evident 

 in the outer region of the central parenchyma, /. t\, in the region 

 which the dorsal and ventral portions of the nervous system 

 occupy. 



In general it is evident then that the multiplication of the 

 parenchyma-nuclei occurs most rapidly in regions of the body 

 about the nervous system. 



Too little is known regarding the arrangement and develop- 

 ment of the proglottidal commissures and nerves in other Cestodes 

 to enable us to determine whether the proglottidal system appears 

 before the proglottids become distinct. 



A number of authors have described the nervous system of the 

 proglottids of various cestodes, but little attention seems to have 

 been paid to the region of formation. It seems extremely prob- 

 able, moreover, that our knowledge of the proglottidal system is 

 incomplete as regards most cestodes. The difficulty of distin- 

 guishing with certainty the nervous tissue, not the lack of interest 

 in the subject, is responsible for this condition. Branches arising 

 from the longitudinal nerves have often been mentioned and 

 among the later writers upon the subject a number (Koehler, '94; 

 Scheibel, '95 ; Liihe, '96 ; Cohn, '98), have discovered in various 

 forms more or less complex systems of commissures between the 

 longitudinal nerves, sometimes forming a highly developed net- 



