ANATOMY OF CESTODES. 



177 



very small. I do not believe, however, that these spaces actually 

 ever held hooks ; their irregularity of form and size is against 

 such a supposition. Nor is there so regular a ring or row of 

 them as would suggest the implantation of hooks. Finally I have 

 ascertained the presence of a chitinous structure which appears to 

 me to represent the otherwise missing hooks, which, at any rate, 

 is difficult to understand on any other hypothesis. This is shown 

 in the accompanying figure (text-fig. 2). It will there be seen 



Text-fiafure 1. 



Horizontal section through anterior end of Amabilia lamelligera, to illustrate 

 very small scolex, which is retracted. 



sc. Scolex showing rostellum and two suckers. 



that the interior part of the rostellum is occupied by a thick ring 

 of apparently chitinous consistency. It is this part which would 

 be external when the rostellum is fully protruded ; and a circular 

 ring suggests in this case a ring of hooks fused together. The 

 armed suckers of the Davaineids present somewhat an approxi- 

 mation to this state of affairs. The minute hooks are so 

 close that they give the collective appearance of a continuous 

 chitinous ring; and it has, I believe, been described as such. 



