(tr) to address or present a petition to (a person in authority, government, etc): to petition Parliament. 6. (foll by: for) to seek by petition: to petition for a change in the law.
An invertebrate is an animal without a backbone. (An animal with a backbone is called a vertebrate.) Invertebrates live in every part of the world. In fact, most of the animals on Earth are invertebrates.Invertebrates come in all different shapes and sizes.Some can be seen only through a microscope.ponges, flatworms, jellyfish, sea. Encyclopaedia EncyclopÃ¦dia, Britannica. Inc an invertebrate is an animal without a. (Backbone an animal with a backbone is called a.) Vertebrate invertebrates live in every part of the. world
trochophore. (invertebrate zoology). A generalized but distinct free-swimming larva found in several invertebrate groups, having a pear-shaped form with an external circlet of cilia, apical ciliary tufts, a complete functional digestive tract, and paired nephridia with excretory tubules. Also known as trochosphere.longside the intestine is a pair of primary mesodermal cells (mesoblasts), which produce a pair of mesodermal bands by repeated division. As a result of further development the trochophore acquires bristles, and its mesodermal bands become segmented, forming a series of paired coelomic sacs.