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

Anther, parts and functions of the anther

parts and functions of the anther

What is phylum hemichordata, What is Phylum Hemichordata ? The name "he...

What is Phylum Hemichordata ? The name "hemi"; (meaning "half") provides a clue to these animals, which have some of the features of chordates, and some features that are chara

INVERTEBRATES - STRUCTURE & FUNCTION, 2. Describe the respiratory organs a...

2. Describe the respiratory organs and mechanism of respiration in pila.

Environment and health- impact of air and water pollution, Environment and ...

Environment and Health- Impact of Air and Water Pollution Environment includes a host of factors of which air and water are the two major components. Air pollution is caused b

Explain health care, Patient Care The primary basic principle in nutrit...

Patient Care The primary basic principle in nutritional practice to be valid must be person/patient- centered.  It must  be  based  on  initial and  continuing  identified  nee

Acetylcholine, Acetylcholine is the chemical released at neuromuscular jun...

Acetylcholine is the chemical released at neuromuscular junctions which binds to receptors on the surface of the plasma membrane of the muscle cells, creating an electrical impuls

What the two pcr amplified strands, You now want to express the gene in E c...

You now want to express the gene in E coli, but unfortunately it has an intron in it that will not be processed out in bacteria, hence it must be removed. (a)  Design P

Schematic representation of curser position of pulse wave, A lot of hemodyn...

A lot of hemodynamic information including maximum and mean velocity, maximum and mean pressure gradients and pressure half time can be obtained from Doppler trace that helps in

Objectives of diabetes counselling, Objectives of Diabetes Counselling    ...

Objectives of Diabetes Counselling      1.  Facilitating decision to start treatment and change life style 2.  Providing psychological, social and emotional support for a.

Shows evidence to see the in environment abd ecology, Shows evidence of the...

Shows evidence of the ability to see the interaction between environment / ecology and genetics /  evolution Some candidates may recognise that evolution can result in less no

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