76 
The Hydatid Tapeworm — ECHINOCOCCUS GRANULOSUS a (Batsch, 1786) 
Rudolphi, 1805. 
[Figs. 124 to 131.] 
Specific diagnosis. — Echinococcus (p. 75) : Strobila very small, 2.5 to 5 mm., excep- 
tionally 6.5 mm. long. Head very small, subglobular, scarcely 0.3 mm. in diameter; 
rostellum prominent, armed with a double row of 28 to 50 hooklets, the large hooks 
22 to 30 // (40 to 45// Leuckart), the small hooks 18 to 22 u (30 to 38 u Leuckart) ; suck- 
ers 0.13 mm. in diameter; neck continues insensibly into the first portion of the 
strobila, which is devoid of segmentation. This is followed by the first segment, 
which is about as broad as long and is sterile. The second segment may be twice as 
broad and four times as long as the preceding and contains male and female organs. 
The third (terminal) segment is gravid; it may attain 2 mm. in length by 0.6 mm. 
in breadth, and contains about 500 eggs. Calcareous corpuscles present. Male 
organs: Cirrus pouch large, 0.5 mm. reaching nearly to median line of segment; tes- 
ticles 70// in diameter, about 60 to the segment. Female organs: Vagina with large, 
elongate, setose dilatation 0.05 mm. in diameter; vagina continues caudad into a 
dilated 0.014 mm. receptaculum seminis; ovaries 2, lobate, submedian, about halfway 
between genital pore and distal end of segment; vitellogene gland sacular, near distal 
end of segment; uterus rather late in developing; “ shell-gland” apparently absent. 
Embry ophores 32 to 36// by 25 to 30//. Habitat, small intestine of carnivorous ani- 
mals ( Canis ). 
Cystic stage may attain the size of a fist o'r even of a babe’s head, but is of slow 
growth, with thick external lamellated cuticle and thin internal parenchymatic 
layer; pedunculate brood capsules form from the latter, and in each of these several 
scolices form. Daughter cysts may also form. Habitat, various organs of herbivo- 
rous and omnivorous mammals. 
Hosts. — Of strobila: Domesticated dog (Canis familiar is) , wolf (C. lupus), jackal 
(C. aureus ), dingo ^ ( C. dingo), cats (Fells catus domestica ), and probably cougar 
( F. concolor) . 
Of cystic stage: Not infrequent in man (Homo sapiens) ; more common in the domesti- 
cated food-animals, cattle (Bostaurus), sheep (Orisaries), goats ( Capra hircus), swine 
(Sus scrof a domestica)] also reported for crab-eating macaque (Macacus cynomolgus), 
Indian lion-tailed macaque (M. silenus), Barbary macaque (Inuus inuus), the argali 
( Ovis ammon), bactrian camel (Camelus bactrianus), dromedary (C. dromedarius) , 
giraffe ( G-iraffa Camelopardalis), wild boar (Sus scrofa), four-horned antelope ( Tetraceros 
quadricomis) , European elk or moose (Alee alces) , zebra (Fquus zebra), horse (E. 
caballus), ass (F. asinus), Malayan tapir (Tapirus indicus), domesticated dog (Canis 
familiaris), leopard (Felis pardus), domesticated cat ( F. catus domestica), ichneumon 
(Herpestes ichneumon), common European squirrel (Sciurus vulgaris), kangaroo 
( Macropus major ) . 
a Synonyms of strobila stage . — T tenia cateniformis of Rudolphi, 1808a, 411, misde- 
termined; T. cucumerina Bloch of Diesing, 1850a, in part; T. serrata [young] of Rcell, 
1852, misdetermined; T. echinococcus Siebold, 1853; T. serrata Juvenalis rollii Kuechen- 
meister, 1853; Echinococcifer Weinland, 1858 (type T. echinococcus ); Tenia n ana van 
Beneden, 1861a; Echinococcifer echinococcus (Siebold, 1853) Weinland, 1861; Ttenia 
echinococca of Koeberle, 1861a; T. [( Echinococcife '■)] echinococcus of Leuckart, 1863; 
T. (Arhynchotsenia) echinococcus of Diesing, 1864a; T. nana (Beneden, 1861) Diesing, 
1864a [not Siebold, 1852]; T. serrata rollii Kuechenmeister of Diesing, 1864a; 
T. echinoccus Linstow, 1878; T. [( Echinococcus )] echinococcus of Railliet, 1886. 
For synonymy of cystic stage see foot notes pp. 77-82. 
&The form from the dingo is said to attain 10 to 30 mm. in length. If these meas- 
urements are correct, this form doubtless represents a new species. 
