Dipyllidium caninum
This tapeworm has a scolex with a retractable rostellum. Retractible rostella are usually very small. The rostellum will form as a cone on the anterior when the rostellum is invaginated; when evaginated, as shown here, there is a slender stalk-like projection covered with small backward projecting spines. In contrast, taeniid tapeworms have large claw-like hooks that occur in distinct rows of around the the edge of a flat, fixed rostellum.
Dipyllidium caninum dried proglottid
The lower proglottid shows white, honeycomb-like egg packets that extruded from the proglottid upon desiccation. An important alternate method to identify tapeworm proglottids passed by an animal is to tear a proglottid apart on a microscope slide and examine the morphology of the eggs or egg packets that are released.
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Image shows the scolex, strobila and mature proglottids of a mature tapeworm. These extremely large tapeworms parasitize cattle and sheep. The mature proglottids are much wider than long. The scolex is large with prominent suckers but does not have an armed rostellum.
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Bursate tail of a male trichostrongyle
Image shows a typical bursa characteristic of nematodes in the superfamilies Trichostrongyloidea, Strongyloidea and Metastrongyloidea. Note the the bursal flaps, bursal rays and spicules of this male. The bursa of this specimen is well developed and the bursal rays are sharply pointed; these features are typical of strongyles and trichostrongyles. In contrast, the bursae of metastrongyles (lungworms) are described as reduced and the tips of the rays are blunt or stubby.
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Image shows the bursate tail and large buccal capsule typical of the Strongyloidea. The buccal capsule of the species is extremely large and cup-like. The worms live in the bowels of cattle and sheep and are pathogenic in large numbers.
Bursate tail of a metastrongyle with blunt blunt rays
This is the bursa of Metastrongylus apri showing the blunted rays characteristic of the Metastrongyloidea. In this genus the bursa appears well developed but the blunted tips of the bursal rays identify the worm as a metastrongyle.
Non-bursate tail with caudal alae and uneven spicules
This is the tail of a male Cylicospirura from a bobcat stomach showing caudal alae and uneven spicule length often seen in genera of the superfamily Spiruroidea. The blunt tip of the worms body can be seen at the posterior end the worm. When identifying worms to superfamily it is crucial to know whether a worm has a bursae or not; the arrangement depicted her would would be typical of a worm that does not have a bursate tail.
Non-bursate tail with caudal alae
This view of a male Physaloptera rara tail shows stalked sensory papillae within the alae and on the body which is typical of members of the Spiruroidea. Sensory papillae are found on worms in other superfamilies as well.
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Buccal capsule of Ancylostoma caninum
This view of the dog hookworm clearly shows the three ventral teeth on the ventral side of the buccal capsule. The cat hookworm, A. tubaeforme, also has two pairs of three teeth. The large buccal capsule and ventral teeth are the primary features for identification and also place this organism in the superfamily Strongyloidea.
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Bunostomum spp (hookworms of herbivores)
These hookworms have a large buccal capsule armed with ventral cutting plates rather than teeth. Uncinaria sp. in dogs and other mammals and the hook worm in humans (Necator americana) have similar cutting plates instead of teeth.
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