48 KEY FOR DIAGNOSIS OF HUMAN HELMINTHS 



(b) Egg yellowish with rather thin shell. 



Metagonimus yokogawai (Plate V, Fig. 7). 



Average size of eggs 28/z by 16/z. 



b. Eggs over 50/z in length; do not contain a fully devel- 

 oped embryo. 



1. Paragonimus westermanii. (Plate V, Fig. 5). 



Size of egg SO/* to 100;u by 52 M to 75 M . 



2. Fasciolopsis buskii** (Plate V, Fig. 1). Size of 



egg 120/x to 130/z by 77 n to 8(V. 



3. Gaslrodiscoides hominis (Gastrodiscus hominus). 



Size of egg 150/z by 72/*. 



4. Diphyllobothrium latum (Dibothriocephalus tatus) 



(Plate V, Fig. 12). Size of egg 55/x to 76 M by 

 41/z to 56/i,' operculum small not sharply defined. 

 Shell thin transparent, light straw color. 

 II. Operculum absent. 



a. Round or slightly oval, containing a six-hooked 

 embryo. 



1. With a thick radially striated, inner shell or em- 



bryophore. 



(a) Taenia saginata (Plate V, Fig. 8). Em- 



bryophore, ovoid, rusty brown, 35ju to 

 - 40/z in length by 20ju to 30ju in width. 



(b) Taenia solium (Plate V, Fig. 9). Embryo- 



phore almost round; brown, 31^ to 36/i in 

 diameter. 



2. With thin membranous inner shell. 



(a) Hymenolepis nana (Plate V, Fig. 10). Oval 



or globular, with two distinct mem- 

 branes; outer 3(V to 60ju in diameter; 

 inner 16^ to 34/z, filiform projections at 

 each pole of inner membrane. 



(b) Hymenolepis diminuta (Plate V, Fig. 11) 



Round or oval; outer membrane 54ju to 

 86,u; yellowish, may be striated; inner 

 membrane 24/i to 40/z by 36ju. 



The eggs of this species are found only occasionally in feces since 

 in man they are usually expelled with the sputum. 



** The distinction between the various species of the genus Fas- 

 ciolopsis described from man are so doubtful that only one is included 

 *in the key. 



