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

Medical surgical nursing, Medical Surgical Nursing: Medical Surgical N...

Medical Surgical Nursing: Medical Surgical Nursing refers to the  nursing care of adults who have  an actual or potential disorder of physiological functi~n.  The practice of

What is initiation delay, Which of the following is the best definition of ...

Which of the following is the best definition of the initiation delay that is seen in all organisms? A. Initiation delay is explained as the time it takes for the pre-initiatio

Interactions between minerals, Interactions between minerals Copper de...

Interactions between minerals Copper deficiency has been identified as a serious problem for grazing ruminants. A deficiency may be due to low concentrations of Cu in forage a

What is hypothalamus, Which of the following is true for ventilation? A...

Which of the following is true for ventilation? A. Interneurons responsible for generating the rhythm of ventilation are located only in the hypothalamus. B. All the central

Why does bark often die and break naturally, Why does bark often die and br...

Why does bark often die and break naturally? The bark is the mature periderm of the stem, branches and roots. It dies and breaks when these structures grow and thus the perider

Explain protostomes vs. deuterostomes breifly, Explain Protostomes vs. Deut...

Explain Protostomes vs. Deuterostomes breifly? Branching Evolutionary Lines : It appears that the Coelomate animals separated into two divergent lines of evolution in terms o

Phylum Coelenterata, Phylum Coelenterata characters anc classification

Phylum Coelenterata characters anc classification

What is mass transportation across the cell membrane, What is mass transpor...

What is mass transportation across the cell membrane? Mass transportation is the entrance or the exiting of substances in or from the cell engulfed by portions of membrane. The

Long-term follow-up results , Long-term Follow-up Results :  To evaluate t...

Long-term Follow-up Results :  To evaluate the long-term results of surgery, one has to take into consideration the natural history, results of medical treatment and that of PTCA.

Define about the polyphenols, Define about the Polyphenols? We now come...

Define about the Polyphenols? We now come to a group of compounds, which were until recently considered to adversely influence nutrient absorption or giving colour to foods e.g

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