Nemertina...
The phylum Nemertina is comprised of non-segmented worms whose anatomy includes: the dagnostic rhynchocoel housing a protrusible proboscis, a closed blood-vascular system lined by endothelium, a regionated gut with anal pore, a fully ciliated and glandular epidermis, a nervous system with four cerebral ganglia and a pair of lateral nerve cords, and serial sacculate gonads. There are about 900 described species of nemertines. They are primarily marine and found in all major marine habitats, but they also are known from freshwater and terrestrial habitats. The size of adult worms ranges from 1 mm to many meters in length and 0.15 mm to a few centimeters in width. The phylum consists of two classes, the Anopla and Enopla, the names reflecting respectively the absence or presence of specialized proboscis armature the stylets.
Interstitial nemertines generally are less than 0.5 mm in diameter and may be up to 50 mm in length, but many are less than 0.3 mm in diameter and 10 mm in length. About thirty species of interstitial nemertines have been described. Of the three orders, the hoplonemertines predominate in taxonomic diversity with 23 species in five genera.
The phylum Nemertina is comprised of non-segmented worms whose anatomy includes: the dagnostic rhynchocoel housing a protrusible proboscis, a closed blood-vascular system lined by endothelium, a regionated gut with anal pore, a fully ciliated and glandular epidermis, a nervous system with four cerebral ganglia and a pair of lateral nerve cords, and serial sacculate gonads. There are about 900 described species of nemertines. They are primarily marine and found in all major marine habitats, but they also are known from freshwater and terrestrial habitats. The size of adult worms ranges from 1 mm to many meters in length and 0.15 mm to a few centimeters in width. The phylum consists of two classes, the Anopla and Enopla, the names reflecting respectively the absence or presence of specialized proboscis armature the stylets.
Interstitial nemertines generally are less than 0.5 mm in diameter and may be up to 50 mm in length, but many are less than 0.3 mm in diameter and 10 mm in length. About thirty species of interstitial nemertines have been described. Of the three orders, the hoplonemertines predominate in taxonomic diversity with 23 species in five genera.
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