Sentence - Annelids left their traces in burrows and casts on the sea-floor

Sentence - The course is segmented into six different sections.

Sentence - A coelom allows compartmentalization to separate biological systems that carry out differing major functions

Sentence - The cuticle is covered with minute, close-set papillae, and bears numerous setae, approximately 0-02 mm.

Sentence - The bristles emanate from outgrowths of the body known as parapodia, which are practically limbs.

Sentence - Earthworms are hermaphrodites, though they cannot fertilize their own eggs.

Sentence - Earthworms are ready to mate when their clitellum is orange.

Sentence - The internal organs are largely repeated metamerically, in correspondence with the external metamerism.

Sentence - A single icefish stood guard to protect the eggs from potential predators like starfish and polychaete worms

Sentence - Terrestrial oligochaetes are commonly known as earthworms and burrow into the soil

Sentence - The gonads and their ducts in the Hirudinea invariably form a closed system of cavities entirely shut off from the coelom in which they lie

Sentence - Most of the body's tissues undergo constant regeneration

Sentence - The algae live in symbiosis with the coral

Sentence - These crustaceans are therefore the vehicle of these nematodes

Sentence - The kidneys were infected with a parasitic worm

Sentence - Other organisms have lost the peritoneum and have regressed to the pseudocoelomate condition.

Sentence - The second cylindrical vessel was found near a different structure in 2006

Sentence - Stinging nettle is a dioecious herbaceous perennial, tall in the summer and dying down to the ground in winter.

Sentence - The flatworms are the first animals to assume pronounced bilateral symmetry.

Sentence - Both saprophytic and facultative parasitic bacteria agree in requiring non-concentrated food

Sentence - Intracellular parasites are endoparasites that live within the cell of the host.

Sentence - Platyhelminthes is a very interesting phylum that contains nearly 20,000 species.

Sentence - Echinoderms are considered the invertebrate group most closely related to the vertebrates.

Sentence - The phylum Platyhelminthes, which are flatworms, are examples of acoelomate animals.

Sentence - The eyes are indicated as black dots behind the cerebral ganglia.

Sentence - The hermaphroditic breeding system was the most abundant by number of individuals of trees and shrubs at all sites

Sentence - Lack of sleep affects the body's physical regeneration which occurs during sleep.

Sentence - Usually there are only a small number of flame cells (fewer than six)

Sentence - On the scolex, there were four suckers and two rows of hooklets

Sentence - These structures, called proglottids, break off from time to time, thus allowing the developing eggs to escape