376 



I. IJIMA AND T. KURIMOTO. 



and belonging to one internal proglottis, are quite variable bat when 

 taken together may be said as approximately equalling or somewhat 

 surpassing the length of those proglottides that show no trace of false 

 demarcations whatever (Figs. 4, 5, and 0). The features of marginal 

 serration as also the manner of indentation of the body-surface 

 essentially agree in all proglottidal boundaries, lx)th true and fnlse, 

 excluding all possibility that the latter might be some mechanical or 

 accidental production. We are inclined to view the phenomenon in 

 the light that the present species of Cestodes has a tendency to 

 produce superficially more proglottides than it does internally, con- 

 trary to the well-known case of Ligalidae in which the external 

 strobilation remains more or less obsolete. In other words, under the 

 crowded state of proglottides in our Bothriocephakis species, one 

 proglottis seems to remain but partially developed, i. e. only super- 

 ficially marked, in order to give necessary space for the full de\elop- 

 ment of certain genital parts (especially uterus, cirrus, and ovary) in 

 its immediate neighbour. The widely distributed testes and yolk- 

 glands develope themselves as well in the abortive as in the other 

 proglottis and are apparently related to the genital ducts and openings 

 of the latter as if they were its own. 



What further seemed to us t(j be of interest with respect to the 

 strobilation of the present species, is the presence, in our sample No. 1, 

 of indications that certain prcjglottides are undergoing re|)eated 

 division. In this anterior region as many as o8 proglottides were 

 counted within a space of 10 mm., giving to each proglottis an 

 average length of 0.26 mm. (l)y o mm. in breadth). The actual 

 lengths were tolerably uniform, excej)t only that the latest formed 

 proglottides were only half or less than half as long as the 

 others. Division of a proglottis int») two takes place, not at its 

 middle, but invariably at its anterior portion; consequently, of the two 



