120 



THE CESTOIDEA 



These "phyllidia" are outgrowths of the scolex, and contain a 

 part of the excretory network (Fig. VII. 2) ; they occur under 

 three chief varieties : (a) They retain their simple character with 

 a more or less marked, spoon-shaped depression or "bothridium" 



PIG. XVI. Scolex of various Tetraphyllidea 



1. Anthobothrium cornucopia, v. Ben., out of Galeus canis (after v. Ben.). The four phyllidia 

 are typically developed, with long stalks, and a simple unarmed and undivided bothridium. 



2. Rhinebothrium flexile, Lint., out of Trygon centrum (al'ter Linton). Each bothridium is 

 divided into numerous loculi by a median, longitudinal, and a series of transverse ridges. 



8. Phyllobothrium thridax, v. Ben., out of Squatina vulgaris (after Zschokke). Each both- 

 ridium is provided with an accessory sucker (a). 



4.Eckeneibothrium variabile, v. Ben., in various species of Raia (after Linton). In addi- 

 tion to the usual four bothridia here well developed carried by the phyllidia, there is an 

 apical, rostellar sucker (x). 



at the free end; the point of attachment to the scolex is con- 

 stricted, and this narrow base may be prolonged to form a distinct 

 peduncle, or this simple depression in the Phyllobothrinae (Fig. 

 XVI. 2) may be subdivided by transverse ridges into a small 

 number of " loculi," as in the posterior sucker of such a Trematode 



