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

Explain risk factors and their role in cad, Explain risk factors and their ...

Explain risk factors and their role in cad ? The concept of risk factors constitutes a major advance for developing strategies to prevent CVD. The Framingham Heat Study played

Determine the significance of siphuncle., Determine the significance of Sip...

Determine the significance of Siphuncle. A cord of tissue that passes between different chambers of a Nautilid shell. Siphuncle regulates the amount of air or fluid in chambers

Anemophily - cross-pollination, Anemophily - Cross-pollination It ...

Anemophily - Cross-pollination It is also commonly referred to as wind pollination, i.e., the pollen grains are carried through wind currents. To ensure good pollination t

How plant transporting substances through tissue, How plants solve the prob...

How plants solve the problem of transporting substances throughout their tissues? In the bryophytes the substance transport is done by the diffusion. In the tracheophytes (pter

How body size and composition affecting the bmr, How Body size and composit...

How Body size and composition affecting the BMR? Basal and resting energy expenditures are related to body size, being most closely correlated with the size of the fat-free mas

Angiosperms, why are the microspores in groups of four?

why are the microspores in groups of four?

Assessment of aplastic anaemia, Assessment   The patient will present w...

Assessment   The patient will present with striking pallor, irritability and lethargy due to anaemia, bledding or bruising and petechiae due to thrombocytopenia, fever and infe

Working of eye, WORKIN G OF EYE - Human eye is sensitive to light wave...

WORKIN G OF EYE - Human eye is sensitive to light wavelenght ranging from 380 - 760 nm. Bees, ants, spiders and gold fish can see uttraviolet light which is invisible to hu

Describe how many bones are there in human foot, Describe how many bones ar...

Describe how many bones are there in human foot The human foot is a great mechanical marvel. It has 26 bones, 29 joints, and 42, various ligaments, a sensitive and protective s

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