Trichostroyxgyh (J cnus from an Armadillo. 415 



Tlie small oral aperture leads direct into the oesopliaf^us, 

 tliere being no indication of a mouth-cap.sulc. Tiie ceso- 

 ])Iia^us (fig. 1 a) is straight, elongate, and slightly thickened 

 posteriorly, measuring on an average about 4.50 }i long and 

 .50 /JL at its broadest part. 



The nerve-ring is situated slightly in front of the middle 

 of the oesophagus. 



The position of the excretory pore does not appear to be 

 constant, in that in some specimens it was situated at the 

 level of the hind end of the oesophagus, whereas in others it 



Fig.l. 



a. Anterior portion of Trichohelix tttbercnlatum (Parona and Stossich 

 1901). b. Head, much enlarged. ' 



£•. P. = excretory pore; iY.^. = nerve-ring ; ^. P. = head-papilla. 



was pushed slightly forwards; the latter position, however, 

 is the more common (fig. 1, a). From the pore the excretory 

 duct passes almost vertically inwards, and on reachino- the 

 oesophagus bends abruptly backwards. 



The bursa (figs. 2 and 3) is short and broad, and is about 

 three times as broad as it is deep ; posteriorly it is slightly 

 notched in the mid-line, and a shallow depression on each 

 side gives it a slight trilobed shape. 



Of all the bursal rays the dorsal is the stoutest. This ray 

 measures about 50 /m broad at its bnse and is about 200 a 

 long. After the origin from it of the externo-dorsal rays 

 it is only about half this thickness. About midway between 

 the origin of the externo-dorsal rays and its tips it divides 

 into two branches, and each of these latter is again split at 

 its tip. Each inner terminal branchlet bears on its inner side 

 a much thinner and parallel twig. 



