300 T. B. ROSSETER OX HYMEXOLEPIS FARCIMIXALIS. 



1 — 1*012 mm. broad. The scolex is subquadrangular (PI. 24, 

 Fig. 1), and possesses four somewhat bossed muscular suckers. The 

 rostellum when dissected out is elliptical (Fig. G), and bears a 

 single row or crown of ten saddle-shaped hooks 0*020 mm. long 

 (the Dicranotaenia form of Raillett). Fig. 7, a, b, c, shows the 

 various forms of hooks given by Krabbe, and d is the hook from 

 one of my specimens for comparison. The posterior root is short 

 and curved in contradistinction to that of T. seiyentvlus (Fig. 8), 

 which is long and slightly arched. It measures 0*006 mm. 

 Another feature is that the anterior root is thick. 



The length of the neck (Fig. 1) varies considerably, being in one 

 of my specimens as long as 0*473 mm. According to Goeze it is 

 0*213 mm. in length, and segmentation commences at this distance 

 from the scolex. In some instances, as exemplified by some of 

 my specimens, there is an exception to this dictum of Goeze by 

 segmentation commencing — as in the case of T. serpentuhis — 

 almost immediatelv from the base of the scolex. This I look 



Mi 



upon as a variety caused possibly by cross-fertilisation. I say 

 " possibly," but I might, perhaps, have used the word " positively," 

 as I have taken different species of avian tape-worms from the 

 intestine of the same bird in the act of cross-coition ; but all my 

 attempts to fix them for mounting under such circumstances 

 have up to the present time failed. Goeze tells us .that the neck 

 is finely punctured, and that the middle segments — " Mittel- 

 glieder " — were studded with delicate cells. Seen with a ^ in - 

 oil immersion lens, these punctures or cells are resolved into 

 minute pigment cells and calcareous corpuscles intermingled 

 with the parenchymatous tissue. The pigment cells are not so 

 numerous as the calcareous corpuscles, yet they are so thickly 

 crow dec! together as to give a dark granular appearance to the 

 neck and early segments (Fig. 10). The older segments are devoid 

 of either pigment cells or calcareous corpuscles. The flat dull 

 globes, as seen by Goeze in the middle segments, are very 

 interesting morphologically. Considering that von Siebold's 

 specimen was but 30 mm. long — this is but a quarter the length 

 that Goeze gives for his worm — and that the terminative 

 segments of von Siebold's worm possessed eggs with six-hooked 



