Ques-1: Development of tube feet of CRINOIDEA Development of tube feet is from the larval stage in Crinoidea (echinoderms) and these tube foot useful for locomotion in adult species. Echinoderms are deuterostomes. Larval forms of echinoderms possess bilateral symmetry and a mouth arises from opposite end of the blastopore and alimentary canal forms connecting both during embryonic development (metamorphosis). Larval form is ciliated & from which this tube foot is developed in adults with pentaradial symmetry during metamorphosis. Adult echinoderms possess a water vascular system associated with external tube feet as well as a calcareous endoskeleton along with ossicles interconnected collagen fibres. Sea urchins often use tube feet along with spines for jerking movement and peristaltic movement. Adult echinoderms possess a water vascular system associated with external tube feet as well as a calcareous endoskeleton along with ossicles interconnected collagen fibres. Sea urchins often use tube feet along with spines for jerking movement and peristaltic movement. These are appeared in sea stars, these openings are smaller, and yellow button like warts located on the aboral surface of sea stars. This opening has other important parts, which perform meticulous function in water vascular system, and these parts are tube feet, stone canal, ring and radial canals. Ques-2: Spine structure of Ophiuroidea (echinoderm) are arranged in 5 rows i& connected to ligaments with mutable collagenous substance. These spines are composed of dermal calcareous ossicles or calcareous spicules Solution Ques-1: Development of tube feet of CRINOIDEA Development of tube feet is from the larval stage in Crinoidea (echinoderms) and these tube foot useful for locomotion in adult species. Echinoderms are deuterostomes. Larval forms of echinoderms possess bilateral symmetry and a mouth arises from opposite end of the blastopore and alimentary canal forms connecting both during embryonic development (metamorphosis). Larval form is ciliated & from which this tube foot is developed in adults with pentaradial symmetry during metamorphosis. Adult echinoderms possess a water vascular system associated with external tube feet as well as a calcareous endoskeleton along with ossicles interconnected collagen fibres. Sea urchins often use tube feet along with spines for jerking movement and peristaltic movement. Adult echinoderms possess a water vascular system associated with external tube feet as well as a calcareous endoskeleton along with ossicles interconnected collagen fibres. Sea urchins often use tube feet along with spines for jerking movement and peristaltic movement. These are appeared in sea stars, these openings are smaller, and yellow button like warts located on the aboral surface of sea stars. This opening has other important parts, which perform meticulous function in water vascular system, and these parts are tube feet, stone canal, ring and radial canals. Ques-2: Spi.