144 PROCEEDINGS OF THE ACADEMY OF [March, 



Immature females were not nearly so puzzling. It was through 

 a consideration of the coils of different specimens at different stages 

 of development, together with reconstructions in wax, that the ar- 

 rangement of the twists was finally made out. 



The sex of the youngest female could only be determined by 

 its greater proportionate breadth. It measured 2.5 mm. in length 

 and 0.2 mm. in width. It was found with the eight males men- 

 tioned above. It was cylindrical, colorless, and showed no internal 

 structure. It was not coiled, but even at this early stage of devel- 

 opment showed by its angulations a disposition to coil. (Plate IV, 

 fig- 3.) 



The next female studied in point of age was coiled in one plane 

 only. It measured 1,000 mc. by 1,050 mc; i.e., only half the size 

 of the mature female. It was colorless, except for the gut, which 

 was black. In this case the body axis could be readily followed. 

 It was 3.5 mm. long. This specimen was fusiform, its greatest 

 diameter, 450 mc, was located at the posterior third of the body, 

 where the bulk of the gut and egg tubes were. The head and a 

 large part of the neck, 0.2 mm., are bent sharply dorsally. The 

 rest of the body then curls tightly ventrally to enclose the head and 

 sharply bent anterior portion. The tail ends sharply in a single 

 point. Its tip is recurved. Egg tubes may be seen in the body 

 cavity, but they contain no ova. (Plate IV, fig. 9.) 



The third female measured 9 mm. in length. This was 

 ascertained by flattening out a small female and forcibly with 

 needles straightening out the coils. The body varies in mdth. 

 Its greatest diameter is 600 mc. It can now be seen that the body 

 cavity bulges out into expansions at several points. The approxi- 

 mation of these expansions to each other, together with a coincident 

 coiling of the parasite, could easily result in the pumpkin-shaped 

 organism so commonly described. The distortion here produced, 

 however, precludes a positive statement in regard to an habitual 

 and orderly arrangement of these expansions along the bod}' axis 

 in the living animal. 



The fourth female in order of maturity contained mature ova 

 (coiled embryo visible). It was chosen because it was not tightly 

 coiled. It was examined in glycerine with a stereoscopic micro- 

 scope. No cover-glass was used, thus eliminating pressure arte- 

 fact. A wax model was made by combining drawings and direct 

 observation. 



The rigidity of the coils in the unfixed female raised the question 



