1913.] NATURAL SCIENCES OF PHILADELPHIA. 145 



whether this was a permanent or a changeable arrangement. It 

 has been already remarked that even in a very young female, where 

 the anlage of the organs was not yet prominent, there was a dis- 

 position (as evidenced by angulations) to coil. This same early 

 disposition is also noted in the half-grown specimen which was 

 tightl}' coiled in one plane. These facts seemed to argue the coiling 

 as a peculiarity of the species. 



To shed further light on the subject, reconstructions were made 

 of two mature females after the wax-plate method of Bonn, and a 

 third (partial) reconstruction in pasteboard. In all three the coils 

 were very tight. In two specimens the head and tail project at 

 opposite sides of the coiled worm. In a third the head and tail are 

 close together. In the two complete reconstructions the tail re- 

 curves in a direction opposite to the general direction of the coils. 

 That is, tracing the coils in a spiral manner down from the head — 

 either clockwise or contraclockwise, as the case may be — we sud- 

 denly come to an abrupt bend toward the tail, where it bends around 

 in the opposite direction. This peculiarity is also seen in the half- 

 grown female mentioned before, and it is this reversal which led to 

 the uncertainty in determining the arrangement by direct examina- 

 tion. As stated above, the coils may (looking at the specimen head 

 on) run clockwise or contraclockwise. 



From a consideration of the camera lucida drawings of females at 

 different stages of development, along with the wax model and 

 reconstructions, the following deductions are made: 



There is a very early "embryonic" propensity for the worm to 

 coil tightly. The arrangement of such coils is not constant, the 

 coils turning either clock\vise or contraclockwise. The head along 

 with a short anterior portion is always bent more or less sharply 

 dorsally. The caudal extremity always twists suddenly in a direc- 

 tion reverse ,to that of the more anterior coils. As the female 

 becomes mature, the remarkable egg content causes a broadening 

 of the worm without a proportionate increase in length. This 

 causes the mass to appear globular. The pressure incident to 

 such enormous egg content ol)literates any "dead spaces" between 

 the coils (internally or externally), and this tends all the more to 

 perfect the globular appearance. 



It is presumed (in the absence of direct observation of living 



specimens) that the worm may alter its coils and protrude head or 



tail into the lumen of the proventricle. It does not seem probable, 



from its bulkiness, that the mature female migrates as does Spirop- 



10 



