28 S. GOTO. 



direct continuation of the investing membrane of the body. 



The pair of suckers above described has been mistaken by Tas- 

 chenberg'^ for the terminal vesicles of the excretory system (see y. 5). 



Calicotyle — Anterior sucker — In this genus the anterior sucker is 

 developed far more imperfectly than in those hitherto described, and 

 is also totally different from them in structure. It is constituted by 

 a deep invagination of the ventral side of the body just behind the 

 mouth (PL XIX, fig. 8). From the inner surface of the investing 

 membrane that lines the cavity of the sucker, numerous muscular 

 fibres take their origin, and diverging in various directions, become 

 continuous with the longitudinal fibres of the body. Besides these, 

 circular fibres are exceptionally developed in this part. Owing to this 

 local development «f the musculature, the anterior sucker seems in a 

 surface view to be pretty well defined from the surrounding mes- 

 enchyma, and to form a distinct organ (PI. XIX, figs. 1 and 4) ; but 

 sections show that this is by no means the case. Morphologically 

 speaking, it would be more correct, therefore, to call it a rudimentary 

 sucker (pseudoventose). 



Posterior sucker — This is situated on the ventral side at the pos- 

 terior extremity of the body. Its ventral surface is marked out into 

 a central heptagonal and seven peripheral areas by elevations of the 

 ventral surface radiating from the wall of the central polygon. This 

 central polygon does not occupy exactly the middle of the sucker, but 

 is situated a little more anteriorly. The hindmost area which is 

 the largest, occupies the median line of the body, while the others are 

 arranged symmetrically on either side, and decrease in size from 

 behind forwards (PI. XIX, figs. 1 and 3). 



Tlie musculature of the sucker consists of three sets of 

 fibres, which may be called the radial, the transverse or dorso-ventral, 



1). Taschenberg— Weitere Beitrage, p. 13. 



