Scolex with 4 suckers and a rostellum that might be armed. Single compact vitellarium. Lateral genital pore. Apolytic proglottid (no uterine pore).
Hymenolepis diminuta
Examine the ovum, comparing to Fig. 4.44 of your textbook (page 139).
Note the hexacanth larva. The larva is infective to beetles, and develops into a cysticercoid
within the hemocoel. The difinitive host is a rat. The eggs of taeniids are similar, but
have characteristic radial striations.
Taenia pisiformis
Examine the scolex, noting the suckers and rostellum armed with a double crown of hooks.
Compare a mature proglottid to Fig. 4.43D in your textbook (page 138), noting the bilobed
ovary, lateral genital pore, and single, compact vitellarium. Examine a gravid proglottid,
noting the increased extent of the uterus. Adults are a common tapeworm of dogs and wild
canids.
Taenia solium
Examine the scolex, noting the suckers and rostellum armed with hooks.
Compare a mature proglottid to Fig. 4.43D in your textbook
(page 138), noting the bilobed
ovary, lateral genital pore, and single, compact vitellarium. Examine a gravid proglottid,
noting the increased extent of the uterus. Adults occur in humans with a swine
intermediate host.
Echinococcus granulosus
Examine the whole mount of the cysticerci, and the section
of the hydatid cyst, comparing to the endogenous budding pathway illustrated in Fig. 6
(page 146) of Box 4.2 in your textbook. Contrast this with the
multilocular cysts of E. multilocularis.
Examine the adult, which is the smallest of the taeniid cestodes, consisting of 3-5 (generally 4) proglottids in addition to the scolex and neck. Compare a mature proglottid to Fig. 4.43D in your textbook (page 138), noting the bilobed ovary, lateral genital pore, and single, compact vitellarium. Examine a gravid proglottid, noting the increased extent of the uterus. The definitive hosts for E. granulosus are domestic and wild canids, and the hydatid cysts occurs in numerous herbivorous mammals, and can infect humans.
Monezia expansa
Examine the scolex and a
mature proglottid, noting the characteristic cyclophyllidean
morphology. Definitive hosts are sheep, with soil mites serving as intermediate hosts for the
cysticercoids.
Scolex with bothria; may have a small number of hooks. Vittelaria and testes diffuse (vitellaria cortical and testes medullary). Genital pore and uterine pore median. Proglottids anapolytic.
Diphyllobothrium latum
Examine the scolex, nothing the bothria (grooves) for attachment.
Compare a mature proglottid to Fig. 4.43C of your textbook
(page 138). The coracidium of Diphyllobothrium latum infects copepods, developing
into a procercoid. Procercoids develop into plerocercoids in fishes, and adults occur in
piscivorous mammals (including humans).
Bothriocephalus cuspidatus
Examine the structure of the scolex, and note whatever
structures you can locate in the proglottids, comparing to Fig. 4.43C of your textbook
(page 138). Bothriocephalus cuspidatus has a similar life cycle to D. latum,
but matures in piscivorous fishes.
Triaenophorus nodulosus
Examine the plerocercoid (which has been freed from a cyst),
noting the 4 hooks on the scolex. Like B. cuspidatus,
T. nodulosus matures in piscivorous fishes.
Scolex with 4 suckers; might have an apical organ. Proglottids are similar to those of cyclophyllideans, but vitellaria occur in lateral bands, and proglottids are anapolytic, with eggs being released through breaks in the body wall. Oncospheres develop into plerocercoids in copepods. Aquatic vertebrates can serve as paratenic hosts, and definitive hosts; in some cases the same individual can serve as both.
Ophiotaenia sp.
Examine the scolex noting the 4 suckers. Compare whatever
structures you can locate in the proglottids to Fig. 4.43A in your textbook (page 138).
This specimen was isolated from the intestine of a bullfrog (Rana catesbeiana).
All 3 specimens you will observe are from the family Ancyrocephalidae
(within the Order Dactylogyrida) characterized by 2 pairs of eyespots, 14 marginal
hooks on the opisthaptor (12 peripheral and 2 central), 2 pairs of hooks (hamuli),
and a sclerotized penis with an accessory piece. Compare the specimens of
Onchocleidus affinis,
O. acer, and O. flieri
to Figure 3.1 and compare Actinocleidus bennetti and
Clavunculus bifurcatus to
Figure 3.2..
