ANIMAL PARASITES 53 



D. Slightly truncate at one end and the delicate operculum 

 with shell projecting slightly behind its edge. 

 E. Egg relatively narrow, average size 30m by 1 1a*. 



Opisthorchis felineus 

 EE. Egg broader, 26m to 30> by 13 M to 16/*. 



Clonorchis sinensis 



DD. Truncate at both ends with dark brown shell, 50m long, 



slightly pointed and tipped with a little shiny clear 



plug, content unsegmented Trichuris trichiura 



CC. Not truncate. 



D. Large eggs, 120 to 160m long, bearing a sharp spine. 

 E. Spine terminal, eggs found in urine and more 



rarely in feces Schistosoma hematobium 



EE. Spine lateral, eggs found in feces. 



Schistosoma mansoni 

 DD. Eggs not spined. 



E. Containing a miracidium, or ciliated embryo; size 

 averaging 83m by 62m, sometimes with slight 

 knob-like lateral thickening. 



Schistosoma japonicum 

 EE. Miracidium not present; embryo tadpole-like or 

 vermiform, or egg content in early segmentation 

 stages. 



F. Very delicate, transparent, asymmetrical 

 shell with double contour, 50m by 80m con- 

 taining well developed embryo. 



Enterobius vermicularis (Oxyuris) 

 FF. Delicate, single-contoured shell, symmetrical, 

 and with broadly rounded ends. A broad 

 clear zone between the shell and the con- 

 tent; normally showing early segmentation 

 stages, but never larvae in fresh stools. 

 G. Ends somewhat pointed, size 75 to 90m 

 by 39 to 47m- 



Trichostrongylus orientalis 

 GG. Ends more broadly rounded, size 58 to 

 80m by 35 to 52 M . 



Necator americanus 

 Size 56 to 61m by 34 to 38m. 



Ancylostoma duodenalc 



References 



Brug, S. L., and G. H. Kloevekorn, 1926. "Die parasitologische Diag- 



nostik der menschlichen Faezes," 64 pp., 8 plates. Barth, Leipzig. 

 Hall, M. C., 1912. A comparative study of methods of examining feces 



for evidences of parasitism. U. S. Dept. Agr., Bur. An. Ind., Bull. 135, 



42 pp. 

 Hall, M. C, 1922. The eggs of dog, cat, and fox parasites. Veterinary 



Med., Apr., 1922. 



