60 ILLINOIS BIOLOGICAL MONOGRAPHS (164 



Plate III 



Fig. 30. Thoracostoma chilensis. Lateral view of head showing the location of an ocellus. 



After Steiner. X370. 

 Fig. 31. Protospirura labiodentata. View en face showing the two tripartite lateral lips and 



the disymmetrically arranged papillae. After von Linstow. 

 Fig. 32. Spirocera subaequalis, showing the buccal armature. See figure 24. After Seurat. 



XSO. 

 Fig. 33. CanuiUanus americanus. Dorsal view of the oral apparatus of a female showing 



the two lateral valves and the dorsal trident. After Magath. XSO. 

 Fig. 34. Gnathostoma spinigerum, dorsal view, showing the two lateral lips and the spine 



beset head. After Baylis and Lane. X40. 

 Fig. 35. Kathleena arcuata. Head en face showing the apparent triradial symmetry and 



large interlabia. After Gedoelst. 

 Fig. 36. Eustrongilides elegans, showing the prominent papillae and the slight tendency 



toward disymmetrical arrangement. After Jagerskiold. X40. 

 Fig. 37. Ascaris ferox {Crossopkorus coUaris). Lateral lip showing the asymmetrical arrange- 

 ment of papillae. After Schneider. X4S. 

 Fig. 38. Triodontophorus minor, lateral view, showing the three pharjoigeal teeth. After 



Looss. XSO. 

 Fig. 39. Scleroslomum equinum, dorsal view, showing the "leaf-crown," dorsal gutter and the 



large buccal cavity. After Looss. X30. 

 Fig. 40. iincy/oiioBJo comnuOT, showing the ventral teeth and capsule. After Looss. XIOO. 

 Fig. 41. Kathleena trkuspis. Head, dorsal view, showing the interlabia. After Gedoelst. 

 Fig. 42. Ascaris rosmari. Lips, viewed en face, showing the large dorsal Up. After Baylis. 



X90. 



