Eutelolecithal is a term used in biology to describe an animal egg that contains a fairly uniform distribution of yolk throughout its structure. The word is pronounced /juːtɛləʊˈsɪθ(ə)l/, with stress on the second syllable. The 'eu-' prefix indicates "well" or "perfectly," while 'telolecithal' is derived from the Greek words 'tele' meaning "complete" and 'oleic' meaning "yolk." Thus, "eutelolecithal" refers to an egg that has a complete and evenly distributed yolk content.
Eutelolecithal is an adjective used to describe the type of egg found in certain animals, particularly invertebrates, where the yolk is evenly distributed throughout the egg cytoplasm. The term is derived from the Greek words "eu", meaning well or good, "telos", meaning end or purpose, and "lekythos", meaning egg yolk.
In eutelolecithal eggs, the yolk serves as the primary source of nutrition for the developing embryo. This is in contrast to other types of eggs such as telolecithal or centrolecithal, where the yolk is concentrated at one pole or in the center of the egg, respectively. The even distribution of yolk in eutelolecithal eggs ensures that the developing embryo has access to a constant supply of nutrients as it grows and develops.
Eutelolecithal eggs are commonly found in many species of marine invertebrates such as mollusks, crustaceans, and some species of annelids. However, they can also be found in certain species of amphibians, reptiles, and fishes.
This type of egg adaptation is important for the survival and growth of the embryo, as it provides a continuous supply of nutrients during the early developmental stages when the embryo is unable to feed independently. Eutelolecithal eggs contribute to the successful reproduction and survival of various animal species by ensuring the proper nourishment and development of the embryo until it hatches or is born.
Noting an ovum in which the deutoplasm of the yolk almost entirely displaces the cytoplasm from one pole.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The word "eutelolecithal" is composed of two main elements: "eutelo-" and "-lecithal".
The term "eutelo-" is derived from the Greek word "eutelēs", which means "complete" or "perfect". It is used as a prefix in scientific terminology to indicate that something is well-developed or fully formed.
The element "-lecithal" is derived from the Greek word "lekithos" meaning "egg yolk". In biological terms, this element is used to describe organisms whose eggs contain a substantial amount of yolk.
Therefore, when combined, "eutelolecithal" refers to an organism or an egg that is well-developed with a significant amount of yolk.