CLASSIFICATION OF LUMBRICUS
PHYLUM :- ANNELIDA (Metamerically segmented, coelomate and laterally symmetrical. )
CLASS :- CLITELLATA (having a clitellum – the ‘collar’ that forms a reproductive cocoon during part of their life cycles.)
ORDER :- OPISTHOPORA (mostly terrestrial worms.)
FAMILY :- LUMBRICIDAE (Large form family of earthworms)
GENUS :- Lumbricus
It is common earthworm of Europe and U.S.A.
HABIT AND HABITAT
Lumbricus is found abundantly in moist soil.
GENERAL CHARACTERSTICS OF LUMBRICUS
- Commonly called as Earthworm.
- Earthworm is a common and favourite classroom animal in European countries.
- It remains wholly in burrow during daytime because of light and humidity.
- Cylindrical body measures 15 to 30 cm in length and consisting of about 100 metameric segments.
- Each segment, except the first and the last bears S-shaped setae on ventral surface as black dots.
- Lobular prostomium divides peristomium into two parts.
- A permanent clitellum develops in segments 33 to 37 only on dorsal and lateral sides, remains incomplet. ventrally. Clitellum contains tuberacle. Tail is flattened.
- Dorsal and ventral surfaces well differentiated.
- Hermaphroditic (monoecious), female-genital pores lie ventrally on 15th segment while male– genital openings on 14th segment. Genital papillae are absent. Reproduction is sexual.
- Dorsal pores are found in the midline of the inter-segmental grooves from the 10th segment onwards.
- Coelomic fluid is exuded from these pores on the surface of the worm, when the worm is subjected to some irritation.
The peritoneum surrounding the intestine is modified to form a glandular layer called the chlorogogen cells. These extract wastes from the blood and later become detached and float in coelom. Ultimately much of their substances is engulfed by amoeboid cells and carried to the skin where it is deposited as pigment.
The Animal contains incomplete clitellum in 33 to 37 mm segments and all above features, hence it is Lumbricus.