445) PSEUDOPHYLLIDEA FROM FISHES— COOPER 157 



"walls" and the fusion of the latter for most of their extent "in such a manner 

 that only a small lateral [dorso ventral] opening in the region of the apex 

 leads into the anterior of the spacious, hollow organ of attachment. " The 

 size and shape of the opening itself varies considerably in preserved material. 

 It may be so small (Fig. 29) as to be seen only on very close examination or in 

 sections, or comparatively large (Fig. 49), depending on the stage of contrac- 

 tion or enlargement of the bothria v>hen the individual is fixed or preserved. 

 During life it may be seen to undergo such variations in size while the whole 

 scolex isbeing elongated and retracted during the characteristic sucking move- 

 ments. Rudolphi (1819:477) correctly described the bothria as ". . . oblonga 

 profunda et magna in vivis; in mortuis bothrii ostium parvum anticum adesse 

 videtur." In lateral view (Fig. 30) the bothria are seen to be more sharply 

 oval or even conical in outline, as is consequently the whole scolex, owing to 

 the fact that the dorsoventral diamxCter of the lumen of each is much greater 

 in its posterior half than in its anterior half. It will also be noted more clearly 

 from this aspect that the hinder borders of the bothria project a considerable 

 distance beyond the true anterior end of the strobila. Thus the length of the 

 scolex is not that of the bothrium., as many writers have evidently taken it to 

 be, but as far as can be determined from external views, more nearly that of 

 thd marginal sulcus plus an extension of the same to the tip of the scolex, or, 

 where the latter is retracted, to the anterior border of the labia. The breadth 

 of the scolex is here taken for the sake of convenience to be that of the bothrium, 

 since there is very little difference between the two in this regard. The two 

 apertures of the bothria are united over the tip of the scolex by a saddle-shaped 

 groove, the edges of which are somewhat swollen so as to form lip-like struc- 

 tures. This groove has been described and figured for C. crassiceps by Molin 

 (1861:235, Fig. 2, Tab. V) and Ariola (1900:397, Fig. 17, Taf. VIII) and 

 figured by Linton (1901a :Fig. 267, PI. 24), but it does not appear either in the 

 figures given by Wagener (1854 :Fig. 75, Taf. 7; 1857 :Fig. 6, PI. II) or that by 

 Johnstone (1909:87, Fig. 14). It is present in all of the writer's material even to 

 the youngest, but in a few cases the tip of the groove, that is the extreme tip 

 of the scolex, is so prominent as to more or less obliterate the lips (Fig. 49). It 

 is also to be noted that the lateral grooves separating the bothria do not pass 

 thru these lips. This is nicely indicated in Ariola's figure but erroneously 

 described by him as ''passando per I'apice," and as further figured but in 

 the same relation by Johnstone. Wagener's figure 75 and Linton's figure 266 

 also give the erroneous impression that this groove passes right over the tip 

 of the scolex. Molin (1861:235), while giving a somewhat confused descrip- 

 tion of the relations between the saddle-shaped structures — which he figures 

 as including the apertures of the bothria more posteriorly — and the lateral 

 grooves, says that he saw in the apex an aperture which not only ended blindly 

 but which was bounded by two eminences, simulating lips. This may have 

 been due to extreme contraction of the tip of the scolex between the hps of this 

 groove. It will be recalled that Leuckart (1819:46) stated in this connection 

 that "An dem Kopfende ist eine kleine Vertiefung in der Mitte; die von den 



