Coxal glands, Biology

Assignment Help:

Coxal Glands

There is a pair of coxal glands, in almost all the segments in Onychophora (Peripatus). Developmentally; in every segment a hollow follicle or somite arises and in the trunk region, they become divided in dorsal and ventrolateral portions. The ventrolateral portion grows into the appendages and its cavity makes the end sac of the coxal gland. The end sac opens by a ciliated canal, the coelomostome, into acoiled excretory canal. The terminal portion of the canal is enlarged to form a vesicle or bladder. So the coxal glands are derived from coelomoducts. In arthropods there is a likeness in the formation of coxal glands from coelomoducts and the creation of gonads and their ducts.

In crustaceans they are found in third and sixth segments and they are suitably. named depending upon the site of their opening to outside. The one located at the base of the third segment opens at the base of the antenna, therefore called antennal gland. The one located in the sixth segment opens at the base of the second maxilla, and is termed as maxillary gland. Antennal gland is present in the larval forms of Ostracoda, Copepoda, Branchiopoda, Branchiura, Cirripedia and lower Malacostraca but TP the adults of these groups have maxillary glands. The adult amphipod and decapod crustaceans comprise antennal glands. Mysidacea, a primitive group of crustaceans have both of the antennal and maxillary glands functional. Most arachnids have a pair of coxal glands opening in the sixth segment, opening at the base of third pair of walking legs. In Limulus, there are four pairs of coxal glands.


Related Discussions:- Coxal glands

What are d-glucose and d-galactose, D-glucose differs from D-galactose onl...

D-glucose differs from D-galactose only in the arrangement around carbon 4. Therefore D-glucose and D-galactose are- Select one: a. enantiomers b. epimers c. mirror ima

Head stream of highland brook zone, Head stream of Highland brook zone ...

Head stream of Highland brook zone This is formed by a number of small streams, which originate from a marsh, a spring or a glacier. This is a small shallow zone with an irreg

Laws of cleavage, L A W S OF CLEAVAGE - 1. Sac's Law - According t...

L A W S OF CLEAVAGE - 1. Sac's Law - According this law, during cleavage each blastomere to form similar blastomere. New cleavae always take place at the right angle of th

Categories of drugs, CATEGORIES OF DRUGS - 1 . ...

CATEGORIES OF DRUGS - 1 . Anaesthetic - Produces anaesthesia 2. Analgesic - Reliev

Define the ascorbic acid - basic concepts, Define the Ascorbic Acid - Basic...

Define the Ascorbic Acid - Basic Concepts? Ascorbic acid is a water-soluble vitamin, whose structure is shown in Figure. You would have noticed that its structure resembles glu

Define age as a determinants of nutrient requirements, Define Age as a dete...

Define Age as a determinants of nutrient requirements? Age: Requirements change with increasing age between birth and maturity. Nutrient requirements per unit body weight are h

Lungs, what''s the role of lungs in terms of excretion? Like the trachea wh...

what''s the role of lungs in terms of excretion? Like the trachea what''s its role in excretory system?

Is all the cartilage in the body the same, Q. Is all the cartilage in the b...

Q. Is all the cartilage in the body the same? There are 3 types of cartilage in the human body: 1) hyaline cartilage; 2) elastic cartilage and 3) fibrocartilage. Hyaline cartil

Metaphase chromosomes, Metaphase chromosomes: Each metaphase chromoso...

Metaphase chromosomes: Each metaphase chromosomes is a duplicated structure which consists of two sister chromatids, attached at a point called centromere or primary constric

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd