ABNORMALITIES IN CESTODE MONIEZIA. I I I 



It would be premature to attempt with the few facts available 

 to reach a final conclusion with respect to the relations of the two 

 processes. There are three possibilities to be considered : the 

 localization of growth and the formation of proglottids may be 

 the result of the appearance of the transverse nerves and com- 

 missures and other parts of the proglottidal system ; the develop- 

 ment of the nervous system may be the result of the appearance 

 of proglottids ; or lastly, both may be effects of a common cause. 

 Which of these three possible views is correct, it is impossible at 

 present to decide. If the first of the three be accepted and it be 

 admitted that some stimulus from the parts of the nervous system 

 as they develop leads to the formation of a proglottid, an expla- 

 nation is afforded of the first appearance of the proglottid as two 

 groups of nuclei on opposite sides of the body, of the position of 

 these groups, of the direction of their growth and of the order of 

 development of the various parts of the proglottid. It would be 

 out of place here to discuss the influence of the nervous system 

 on growth, differentiation, and regeneration in general, but that 

 such an influence has been found to exist in many cases cannot 

 be denied. 



If we accept either of the other two possibilities, no explana- 

 tion of the observed method of proglottid-formation can be given 

 at present. 



The development of the nervous system and the process of 

 proglottid-formation in different cestodes certainly offers a most 

 interesting field for research. 



2. THE GROWTH OF THE PROGLOTTIDS. 



The further history of the proglottid concerns its growth in 

 size, various alterations in shape and the development of the gen- 

 ital organs. It is beyond the scope of this account to enter into 



A 



FIGS. 60. FIG. 61. 



the details of the formation of the genital organs, but some 

 features of the growth require consideration. 



Figs. 6063 are outline drawings of the form of the proglottid 



