Question

urochordata write about

Answer 1

Hey,

Urochordata( Gr. uros-tail & chordata-notochord)

-Adults are generally symmetrical.
-This sub-phyllum is also called tunicata because the adult body is enclosed within a leathery test or tunic formed of a cellulose-like organic substance termed tunicin.
-The notochord is only present in the tail of the larva and disappears in the adults.
-The dorsal tubular nerve cord is found in the larva it is replaced by a dorsal ganglion in adults.
-The pharynx is perforated by numerous apertures called stigmata formed by larval gill slits.
-The larva is motile and undergoes reterogressive metamorphosis i.e., change from better developed larva to less developed adult.
-Excretory organ is neural gland.

EXAMPLES
Herdmania(sea squirt)
Ascidia
Ciona
Doliolum
Salpa

HOPE THIS HELPS YOU.

Answer 2

Urochordata. ( is also known as tunicata) comprise a subphylum of the phylum Chordata, the group that includes vertebrates. Although tunicates are close relatives of the vertebrates, this relationship is not superficially obvious. The basic tunicate body form includes a body covered by a “tunic” made of a cellulose-like polysaccharide, a notochord that is restricted to the tail and usually present only in larval stages (with the exception of adult appendicularian tunicates), a dorsal nerve cord present in larval stages, and a U-shaped gut. The pharynx (branchial chamber) typically has numerous mucus-covered gill slits. Water flows into the mouth and pharynx via an incurrent siphon and exits via an excurrent siphon; the anus empties into the excurrent flow just as it leaves the body. Nearly all tunicates are marine suspension feeders, but this is otherwise a very diverse group. Although the larvaceans are entirely sexual, many tunicates also reproduce asexually. Most tunicate species are hermaphroditic.