Types specimens of echpnodermata, Biology

Assignment Help:

Types specimens of echpnodermata

Before we begin the study of the selected specimens of the following echinoderms - Feather star, Brittle star, Sea urchin, Sea cucumber and Star fish. You should be aware that though members of the various classes of ecchinoderms often appear to be superficially different, however their structure is fundamentally similar. For example sea cucumbers tack the five arms of sea stars, but they do have five bands of tube feet and thus show the same basic pentaradiate symmetry.

Antedon is commonly called "feather star" or "sea lily" Examine the specimen and note the following features:

(i)The body of Antendon is made of a central convex disc of calyx and five equidistant, elongated slender radiating arms.

(ii)Each arm is divided into two branches at the base, so there are in effect ten long arms.

(iii)The arms are slender, flexible, movable and bear small spine-like structures or pinnules on the two sides.

(iv)The body has a distinct upper oral and lower aboral surface.

(v)Aboral surface bears several root-like, slender, curved, jointed cirri supported by small ossicles which help to attach Antedon to rocks.

(vi)Oral surface is covered with a soft and leathery skin, called tegmen and this surface bears the mouth and anus on the same side of the calyx. The anus is borne on a tiny papilla and is excentric whereas the mouth is in the center.
 
(vii)Five ambulacral ciliated grooves radiate from the mouth towards the arms. Each groove divides into two and runs along the oral surface of each arm.

(viii)The intervening body surface is the adambulacra.

(ix)Tube feet or podia are without suckers and can be seen along the edges of ambulacral groove.

(x)The exoskeleton is made of calcareous ossicles or plates.


Related Discussions:- Types specimens of echpnodermata

What type of building block is atp, Please show a diagram of the ATP molecu...

Please show a diagram of the ATP molecule and label the major parts ot this molecule. Also, what kind of building block is ATP?

Transport of instruments to the sterilization area, Most dental offices hav...

Most dental offices have a designated area for instrument reprocessing that is separate from the dental treatment room. This is ideal, since cleaning, sterilizing and storing instr

What are the functions of biotin, What are the functions of biotin and pant...

What are the functions of biotin and pantothenic acid for the body? How are these vitamins obtained? Biotin (also called as vitamin B8) is a vitamin that acts in the metabolism

What is diabetes mellitus, Question 1 What is diabetes mellitus? Discuss b...

Question 1 What is diabetes mellitus? Discuss briefly its pathogenesis. Explain how would you diagnose this disorder Question 2 Discuss the following Glucose tolerance

What is hipot test ?, Hipot is an abbreviation for high potential. Usually,...

Hipot is an abbreviation for high potential. Usually, Hipot is a term given to a class of electrical safety testing instruments used to confirm electrical insulation in finished ap

Tricuspid valve replacement, Tricuspid Valve Replacement :  It is don...

Tricuspid Valve Replacement :  It is done for organic tricuspid valve disease and at times for functional tricuspid I regurgitation. When done along with other procedures, it

Significant for chromosomes, Q. Why is it significant for chromosomes to be...

Q. Why is it significant for chromosomes to be condensed during mitosis and decondensed during interphase? During mitosis the major problem to be solved is the correct separati

Domestication - wildlife, Domestication - Wildlife It means that man h...

Domestication - Wildlife It means that man has taken under his direct care the living beings which are useful to him. Through extensive breeding programmes, he has modified th

Find out surface area, If given this in this sequence to find surface area,...

If given this in this sequence to find surface area, 1 cm x 2 cm x 2 cm block, am I to assume it is written in LxWxH format? I actually think the length is 2 though and the width i

Acupunture-osteopathy-herbal therapy, Alternative Therapies Assignment 1...

Alternative Therapies Assignment 1. A. Acupunture, B.  Osteopathy, C.  Herbal therapy For each one of alternative therapies above, answers the three questions below! 1. Th

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