50 ON A GYROCOTYLE FROM C HIM. ERA, 



comparison, to correspond to the scolex end* in the segmented 

 Cestodes, and to that at which the mobile organ is situated in 

 Caryophyllaeus. •'' 



Lonnberg has shown that G. urna is subject to verj' remark- 

 able variations in form. In its normal condition it has the lateral 

 borders and the characteristic posterior funnel-like organ thrown 

 into a number of complicated plaits. But in some examples the 

 plaits of the lateral borders, or of the funnel, or of both, may be 

 entirely absent; and in some the funnel becomes replaced b}^ a long 

 cylindrical tube. This modification of the funnel has not been 

 observed in G. rugosa ; but living specimens of that form have 

 not been studied : the degree of folding of the lateral l)orders 

 has been observed to be subject to variation 



In view of these variations it becomes difficult to fix upon any 

 definite and constant differences between the form from Chimccra 

 monstrosa and that from CaUorhynchus antarcticus. Braun 

 suggests that the position of the reproductive apertures may 

 afford a means of distinguishing between them. 



Spencer's account of these apertures in G. rugosa is somewhat 

 confusing owing to certain inconsistencies in the text, and has to 

 be interpreted with the aid of the figures. He describes the 

 presence on the "left" side ventrally of a well-marked somewhat 

 conical and muscular papilla. The male aperture is " on the 

 ventral side just at the base of the papilla, towards the middle 

 line." This statement is not borne out by an examination of the 

 only specimen of G. rugosa at my command at present, in which 

 the aperture is situated at the extremity of the papilla, and is 

 not consistent with Spencer's own figures, one of which (Plate ii., 

 fig. 1) represents th". opening in question as situated on the mar- 

 gin or approximately so, and another (fig. 4) shows it on the 



* That the rejection of Hinnberg's and Spencer's views on the orientation 

 of Gyrocotyle appears also to lead, as Benham (1) points out, to a reversal of 

 the usual view with regard to the position of the sucker in AmphUina need 

 only be mentioned here. 



