12 
and examine first under a medium-power and later under a high-power 
dry lens. In some cases i DibofJrr'Ocej Jurf as and Diplogonojporus ) 
there is a chance of confusing the eggs with those of trematodes: see 
key.p. 9. in Illustrated Ivey to Trematode Parasites of Man. In these 
examinations the 2 by 3 slide is more convenient to work with than 
the ordinary 1 by 3 slide. 
KEY TO THE EGOS OF TAPEWORMS REP ORTED FOR MAX. 
For species thus far found in man in the X’nited states follow roman type. 
1. Eggs provided with a "cap'' or operculum, like the egg of certain liver 
flukes, hut n o: containing an embryo when found in the stools: Diboih- 
riocephalidtz 9 
Eggs not provided with 'cap " or o erculum: round to oval: may occur 
in clusters "egg sack-" . and always contain a 6-hookei embryo 
1 onehosphere when found in the stools: Tamiidse 2 
T.EXIIDE. 
2. Egg with thick, radially striated inner shell (embryophore); Tseminae 3 
Egg with thin, membranous, inner shell 6 
T ex t a. a 
3. Occurrence in btful; rare f the t ill 5 
Positively known to occur in man 4 
4. Embryophore inner shell ovoid, rusty brown, 35 to 40 by 20 to 30 u: 
outer shell delicate with 1 or 2 polar filaments, not usually present on 
eggs in feces: this is the most common Te in the United States: the 
fat tapeworm Taen ia saginata p. 27) 
Embryophore almost round, usually brown, 31 to 36 u; comparatively rare 
in the United States: the pork tapeworm T. solium (p. 37) 
Embryophore oval, whitish to yell swish, 39 by 30 u; reported for Nebraska; 
Ward’s tapeworm T. confusa p. 44) 
Embryophore 31 to 39 by 33.8 jli; repo .1 Africa T. africana (p. 32 
R ssia T. hominis (p. 36) 
5. Embryophore ovoid , 36 to 40 by 31 to 36 u T. pisiformis (p. 41) 
Embryophore globular, 31 to 37 u T. teniseformis (p. 43) 
6. Eggs occur in egg-sacks 8 
Eggs do not occur in egg-sacks 7 
HYMEN" O LE PIS. 
7. Eggs oval or globular: 2 distinct membranes; outer membrane 30 to 60 u; 
inner membrane 16 t :• 34 u, presenting at each pole a more or less con- 
spicuous mammillate projection; common in some localities; the dwarf 
tapeworm I H. nana p. 51) 
Eggs round or slightly oval: outer membrane 54 to S6 u; yellowish, may be 
radially striated: inner membrane 24 to 40 by 20 to 35 it, with mammil- 
late projection at each pole, often not apparent: rare in man 
H. diminuta p. 54) 
Eggs oval or spherical; outer membrane 50 to 100 by 35 to 100 p; inner mem - 
e 30 to 40 by . ccasionally with polar papillae; exceedingly rare in 
man II. lanceolata p. 58) 
- I: is not always safe to- rely upon the egg alone in distinguishing the different 
species. 
