抄録
In studying the life history of the chicken tapeworm, it is quite important for us to investigate the process of development and period from a cysticercoid to a mature tapeworm in its host. But up to the present, little study has been made on the former, while on the latter only the following has been touched; the period—from the time when a cysticercoid enters into the chick to the first excretion of the separated segments from its host—is regarded as the period of development in which a cysticercoid develops into a mature tapeworm. However, when a chick is infested with many tapeworms, it is doubtful which tapeworm will develop into a mature one and separate segments, and moreover, when we observe the first separated segments, we are apt to overlook them, so it is much more trustworthy to determine the period of development in which a cysticercoid develops into a mature tapeworm in the shape of the terminal segment of each of the tapeworms collected through cutting open the small intestine of the chick than to determine it by the excretion of the first separated segment from its host.
In 1938 Luttermoser observed the terminal segments of Raillietina cesticillus by comparing with one another and he named the terminal segment of the tapeworm, which developed into a mature tapeworm with its first terminal segment as yet unseparated“the original terminal segment”, and described that the original terminal segment had its special shape which was different from other segments of the strobila, but he mentioned nothing about it in detail.
The author, therefore, observed the shape of the original terminal segment of R. (P.) kashiwarensis, and made the result of the observation a factor for determining the period of development in which a cysticercoid developed into a mature tapeworm.
