seta

…(or coelom), movable bristles (or setae), and a body divided into segments by transverse rings, or annulations, from which they take their name. The coelom is reduced in leeches, and setae are lacking a few specialized forms, including leeches. A major invertebrate phylum of the animal kingdom, the annelids number…

…Chaetopoda because both groups possess setae. Other systems would join the oligochaetes and leeches in a single class, called the Clitellata, because both groups possess a clitellum. The Archiannelida and Myzostomida treated as polychaete orders in the classification system above have been considered as separate classes in the past. The…

…the abdominal appendages; special egg-containing setae secrete a cement that flows over the eggs and binds them to the setae. Most of the superorder Peracarida, some isopods, such as Sphaeroma, many branchiopods, the Notostraca, and the order Anostraca have a brood pouch on or behind the limbs that is often…

…of bristles known as primary setae. The position and number of setae are constant in each species and so are important in classification. Often there are many secondary setae, giving the caterpillar a hairy appearance. Larvae that live and feed as borers, burrowers, or miners are mostly plain. Those that…

…is made up of brushlike setae. The tips of each seta divide hundreds of times into tiny spatulae (spoon-shaped strands); the final strand is less than 0.25 micrometre (0.00001 inch) in diameter. (A tokay gecko [Gekko gecko], for example, has about half a million setae on each foot.) These fine…

II. Mechanisms for dealing with large particles or masses.

…which penetrates the gametophore, the seta, with an internal conducting system, and a terminal sporangium. The seta contains chlorophyll when immature and cannot absorb moisture from the environment because its surface is covered by a water-impermeable layer, the cuticle. The sporophyte is photosynthetic when immature, but its restricted amount of…