clitellum


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clitellum

[klə′tel·əm]
(invertebrate zoology)
The thickened, glandular, saddlelike portion of the body wall of some annelid worms.
References in periodicals archive ?
zulu Specimens One clitellate; Only one, with and their one with clitellum not maturity developing fully developed tubercula pubertatis Characters Length Large, 185 mm abscised Diameter 12 mm 9-11 mm Prostomium Not observed Epilobous, short, broad Number of Abscised, 135 segments not observed Setae Minute, Minute, only difficult to on some segments, detect closely paired Annulation Not described; 4(?
Body wall thin and transparent, both epidermis and longitudinal musculature 7-9 [micro]m thick; in prostomium and clitellum epidermis is thicker.
crassa, which was described on a single, not fully mature specimen with no clitellum, having two pairs of nephridia per segment, with the gizzard in segment 7(
As from segment 9, ab may be associated with papillae, which occasionally extend on a few segments beyond clitellum.
Clitellum saddle-shaped, segmented, whitish grey, extended dorsally between ab setal lines.
Clitellum on 13-19, circular, incomplete, interrupted by genital field on 17.
Setae absent in clitellum in some specimens but present in others.
Ljungstrom (1972a) likewise collected parthenogenetic morphs with spermathecae and seminal vesicles reduced or absent, and also with an abnormally placed or shaped clitellum.
Holotype: Contracted length 320 mm, diameter after clitellum 20 mm.
schistocephalus Michaelsen, 1897, but the new species is easy to distinguish because of its longer clitellum (21-40 in schistocephalus, 22-27, 48 in proboscideus) and the higher number of spermathecae (1-3 in schistocephalus, 6-9 in proboscideus).
Possibly these two last species are related, differing only in the shape and location of the clitellum and tubercula pubertatis.
Both species might be related, although differ in the shape and location of clitellum and tubercula pubertatis.