154 s. GOTO. 



side, so that a cross-section through it is somewhat cbo- shaped. 

 Under the pressure of a cover-glass, this portion asstunes a somewhat 

 oval form — a circnmstance which probably induced v. Nordmann^^ 

 and Paulsom' to indicate it as an oval "Scheibe." Van Beneden^-* further 

 speaks of" un pédicule " by which the " deux organes ", which carry 

 the suckers, are attached to the body ; but I have not observed any 

 such structure in my species, and it is probably due to a deformation 

 cause<l by pressure and the extreme mobility of this part. The pos- 

 terior margin of the body shows either a nearly straight line 

 or, more commonly, a slight concavity (Fig. 2).^^ Toward this 

 concavity, the body again becomes thicker, the thickening begin- 

 ning this time in the median line, and thence spreading toward the 

 sides, as indicated in Fig. 2, where the shading is made as if this 

 portion were seen from the ventral side, on a longitudinal section, 

 therefore, which does not pass through the hiteral suckers, the bcjdy 

 is seen to present posteriorly a club-like thickening, and end suddenly 

 as if it were cut off. Van Beneden speaks of an "excavation plus ou 

 moins profonde," by which he no dcndjt means the hollow, just spoken 

 of, between the suckers. 



The peculiar sudden bend (Knickung) towards the ventral side, 

 which the body of the worm suff'ers at the place of crossing, has 

 already been noticed by Zeller. There is, however, another feature not 

 observed by him. If the worm, ijamely, is viewed from the p(^sterior 

 end, or if sections of this part are cut, it will easily be noticed that 

 the bodies of the two individuals do not stand exactly opposite each 



1) Xorduiaun — 1. c. p. 60. 



2) Paulson — Zur Anatomie v. Dipl. paradoxum. Mém. d. I'acad. St. Petersbour>^. VIT. 

 Sér. T. IV. 1862. p. 4. I have not been able to gain, access to this work, and am indebted for its 

 account to Prof. Ijiuia's notes. 



3) P. J. V. Beneden — Mémoire sur les vers intestinaux, p. 41. 



4) The European species shows a decided convexity. 



