The characteristic larva of Phylum- 'Coelenterata' is
planula
cysticercus
rhabdiform
wriggler
A.
planula
Coelenterata or Cnidaria shows both sexual and asexual reproduction. The larval stages are planula (Obelia) and ephyra (Aurelia).
Cysticercus is a bladder worm and the third level stage in Taenia. It is visible after the hexacanth is released in the stomach of pig, which goes in the blood circulation and on reaching muscles appears as bladderworm.
Rhabditiform is the first larval stage in Ascaris. It is a non- infective juvenile stage which rests for a week and completes first moult within egg and becomes second stage which is infective.
Wriggler is the larva of mosquito. It is free swimming, active, aquatic larva performing wriggling movements. It has life span of 3- 4 days.
Moulting hormone is secreted by
corpora cardacum
corpora allata
neurosecretory hormone
prothoracic gland
