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Sea urchins are members of the phylum Echinodermata, which also includes sea stars, sea cucumbers, brittle stars, and crinoids. Like other echinoderms, they have fivefold symmetry (called pentamerism) and move by means of hundreds of tiny, transparent, adhesive "tube feet". The symmetry is not obvious in the living animal, but is easily visible in the dried test. Echinodermate means "spiny skin" in Greek.
Specifically, the term "sea urchin" refers to the "regular echinoids", which are symmetrical and globular. The term includes several different taxonomic groups: the order Echinoida, the order Cidaroida or "slate-pencil urchins", which have very thick, blunt spines, and others. Besides sea urchins, the class Echinoidea also includes three groups of "irregular" echinoids: flattened sand dollars, sea biscuits, and heart urchins.
Together with sea cucumbers (Holothuroidea), they make up the subphylum Echinozoa, which is characterized by a globoid shape without arms or projecting rays. Sea cucumbers and the irregular echinoids have secondarily evolved diverse shapes. Although many sea cucumbers have branched tentacles surrounding the oral opening, these have originated from modified tube feet and are not homologous to the arms of the crinoids, sea stars, and brittle stars.
So, yes. Yes they are.
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Can you give me a sentence with the word urchin?
What does an urchin look like?The Urchin is a spiky animal that lives in the Ocean.
Is an urchin a flower?
No, an urchin belongs to the Animal Kingdom.
What are Sea urchin?
The classification of a Sea Urchin is Echinoidea
Are sea urchins amphibians?
no, mammals are grouped together because they all posses hair, lungs and mammary glands (hence the name) to produce milk, and a few other features. the urchin does not posses any of these quality's and therefore is not a mammal
What is the singular possessive for urchin?
The singular possessive form is urchin's.
When was Urchin - album - created?
Urchin - album - was created in 1998.
When was Shingle urchin created?
Shingle urchin was created in 1758.
When was An Urchin in the Storm created?
An Urchin in the Storm was created in 1987.
When was Collector urchin created?
Collector urchin was created in 1758.
The gonads of the are considered to be a delicacy?
sea urchin
Urchin use this word in a sentence?
I didn't really understand that. But I will use the word "urchin" in a sentence. Here I go:Why is there an urchin in my bed?
How does the sea urchin moves?
A sea urchin does move, but not very frequently.
