104 



THE CESTOIDEA 



thickness approaches their lateral diameter or breadth. They 

 thus become sub-cylindrical, and at the same time the constrictions 

 between them become gradually less and less distinct, till finally 



Fio. III. 



1. Bothriocephalus latus, L. The proximal part of a strobila, with successive portions from 

 the more distal region (reduced after Leuckart). a, the scolex, showing the ventral bothrium 

 h indicates the uterus, containing eggs; i, terminal proglottid. 



2. The scolex of Bothriotaenia infundibuliformis, Rud. ( = B. proboscideus, Rud.). From the 

 salmon. (Magn., orig.). n, one of the two deep bothria ; b, c, its right and left lips. 



8. The scolex of Solenophonis (Bothridium) megalocephahts, Crepl., out of the intestine of 

 python. (Magn., orig.). It is seen from the side, so as to show the dorsal and ventral bothria, 

 each of which is a tube formed phylogenetically by the union, along part of their extent, of the 

 right and left lips (/<, c) of the bothrium ; a, the cavity of the tube, the inner margin of the wall 

 being indicated on the right of the figure by dotted lines ; d, the small proximal opeuing ; e, 

 the wide, distal opening, which is provided with a couple of valve-like folds ; g, the commence- 

 ment of the strobila. 



4. Ventral surface of a proglottid, with portions of two neighbouring ones, of B. latus, L. 

 p, The atriopore copulatory pore common to both male and female ducts ; in the lower pro- 

 glottid the cirrus (s) is represented as everted ; it, the uterine pore ; r, region of the proglottid 

 occupie 1 by the testes and vitellaria. 



6. A ventr.il view of a proglottid of Bothriotaenia, Disymphytobothrium, and other genera, 

 in which the atriopore (p) is marginal. 



6. Scolex of Dnthiersia elegaiis, Perr., out of Varaniis. (Magn., orig.). The lips (b, c) of 

 each bothrium are united proximally to form a funnel, the margins of the upper opening are 

 much folded ; d, proximal opeuing. 



they disappear. This region is the " neck," and it is at this point 

 that new proglottids are -being constantly formed. 1 



1 In a few instances, such as D. punctatus and a species from Japan, there are 

 apparently intercalated proglottids, as if a proglottid had budded off another one. 

 But this is not the case ; it is due to incomplete formation of a proglottid. In some 

 species each young proglottid contains 2-6 sets of genital organs one behind the 

 other, but the adult joint has only one set (Ijima). 



