1913.] NATURAL SCIENCES OF PHILADELPHIA. 151 



Fig. 3. — Female T. contorta. This is the youngest female found. It tends to coil 

 even at this early stage. 



Fig. 4. — Female T. contorta. A mature specimen, showing the cuticular expan- 

 sions and subglobular form of this nematode. 



Fig. 5. — Female T. contorta. A mature specimen showing the same general 

 features as the preceding. 



Fig. 6. — Tail of female T. contorta. 



Fig. 7. — Ova of T. contorta. The unilateral bib is represented on one. 



Fig. 8. — Female T. contorta. A mature specimen, showing course of oesophagus 

 and intestines. 



Fig. 9. — Female T. contorta. This is a half-grown specimen. It is coiled in one 

 plane only, and shows the head bent sharply dorsally. It also shows the 

 constant feature revealed in the wax reconstructions, viz., the caudal portion 

 bends sharply in a direction opposite to the general coiling of the worm. 

 This figure is drawn on a much larger scale than the preceding. 



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