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The earthworm works through the ground by insinuating its pointed head between the grains of dirt, (Hooker, 1882).

Earthworm

The earthworm works through the ground by insinuating its pointed head between the grains of dirt, (Hooker,…

Side view of internal structures of earthworm.

Earthworm

Side view of internal structures of earthworm.

Dorsal view of internal structures of earthworm after cutting through the dorsal wall lengthwise and turning it outward.

Earthworm

Dorsal view of internal structures of earthworm after cutting through the dorsal wall lengthwise and…

Cross section of earthworm.

Earthworm

Cross section of earthworm.

Earthworms are segmented worms that live in the earth.

Earthworm

Earthworms are segmented worms that live in the earth.

"Transverse section of the intestine of the Earthworm. ty, typhlosole, an infolded longitudinal ridge in the gut in which the fland cells (gl.) are especially aggregated." — Galloway

Earthworm

"Transverse section of the intestine of the Earthworm. ty, typhlosole, an infolded longitudinal ridge…

The earthworm.

Earthworm

The earthworm.

An illustration of an earthworm. The basic body plan of an earthworm is a tube, the digestive system, within a tube, the muscular outer body. The body is annular, formed of segments that are most specialized in the anterior. Earthworms have a simple circulatory system. They have two main blood vessels that extend through the length of their body: a ventral blood vessel which leads the blood to the posterior end, and a dorsal blood vessel which leads to the anterior end. Most earthworms are decomposers feeding on undecayed leaf and other plant matter, others are more geophagous.

Earthworm

An illustration of an earthworm. The basic body plan of an earthworm is a tube, the digestive system,…

An illustration of an earthworm escaping a cocoon.

Earthworm Escaping Cocoon

An illustration of an earthworm escaping a cocoon.

An illustration of the reproductive system of a female earthworm which is located in the eleventh to the fourteenth segment. "sp. o, its external orifice; sp. sac, spermathecal sac; av, sac containing ovary; r.o, egg; od, oviuct." (Britannica. 1910)

Female Earthworm Reproductive System

An illustration of the reproductive system of a female earthworm which is located in the eleventh to…

An enlargement of the reproductive organs of a earthworm. "sp, Spermatheca; sp',Spermathecal sac involving the last; ov, Ovary; r.o. Egg sac; od, Oviduct." (Britannica, 1910)

Female Earthworm Reproductive System

An enlargement of the reproductive organs of a earthworm. "sp, Spermatheca; sp',Spermathecal sac involving…

"Gregarina, contents divided into pseudo-navicellae. GREGARINIDAE. A family or other major group of endoplastic protozoans, having spheroidal, ovoid, or elongated bodies, sometimes with a segmental constriction, and occasionally one end of the body beaked with an epimerite bearing curved horny spines." -Whitney, 1911

Gregarina

"Gregarina, contents divided into pseudo-navicellae. GREGARINIDAE. A family or other major group of…

"Gregarina, contents divided into pseudo-navicellae. GREGARINIDAE. A family or other major group of endoplastic protozoans, having spheroidal, ovoid, or elongated bodies, sometimes with a segmental constriction, and occasionally one end of the body beaked with an epimerite bearing curved horny spines." -Whitney, 1911

Gregarina

"Gregarina, contents divided into pseudo-navicellae. GREGARINIDAE. A family or other major group of…

"Gregarina, free pseudo-navicellae. GREGARINIDAE. A family or other major group of endoplastic protozoans, having spheroidal, ovoid, or elongated bodies, sometimes with a segmental constriction, and occasionally one end of the body beaked with an epimerite bearing curved horny spines." -Whitney, 1911

Gregarina

"Gregarina, free pseudo-navicellae. GREGARINIDAE. A family or other major group of endoplastic protozoans,…

"Gregarina of Earthworm, encysted. GREGARINIDAE. A family or other major group of endoplastic protozoans, having spheroidal, ovoid, or elongated bodies, sometimes with a segmental constriction, and occasionally one end of the body beaked with an epimerite bearing curved horny spines." -Whitney, 1911

Gregarina Encysted

"Gregarina of Earthworm, encysted. GREGARINIDAE. A family or other major group of endoplastic protozoans,…

"Gregarina of Earthworm. GREGARINIDAE. A family or other major group of endoplastic protozoans, having spheroidal, ovoid, or elongated bodies, sometimes with a segmental constriction, and occasionally one end of the body beaked with an epimerite bearing curved horny spines." -Whitney, 1911

Gregarina of Earthworm

"Gregarina of Earthworm. GREGARINIDAE. A family or other major group of endoplastic protozoans, having…

"Gregarina, their free amoebiform contents. GREGARINIDAE. A family or other major group of endoplastic protozoans, having spheroidal, ovoid, or elongated bodies, sometimes with a segmental constriction, and occasionally one end of the body beaked with an epimerite bearing curved horny spines." -Whitney, 1911

Amoebiform Gregarina

"Gregarina, their free amoebiform contents. GREGARINIDAE. A family or other major group of endoplastic…

Leeches are parasitic worms.

Leech

Leeches are parasitic worms.

"Lumbricus agricola. A, entire specimen, lateral view; B, ventral view of anterior portion of the body, magnified. 1, 15, 33, first, fifteenth, and thirty-third segments. The black dots represent the setae." -Parker, 1900

Lumbricus Agricola

"Lumbricus agricola. A, entire specimen, lateral view; B, ventral view of anterior portion of the body,…