Printer Friendly
Dictionary, Encyclopedia and Thesaurus - The Free Dictionary
3,589,752,703 visitors served.
forum Join the Word of the Day Mailing List For webmasters
?
Dictionary/
thesaurus
Medical
dictionary
Legal
dictionary
Financial
dictionary
Acronyms
 
Idioms
Encyclopedia
Wikipedia
encyclopedia
?

Protostomia
(redirected from Protostome)

    Also found in: Dictionary/thesaurus, Medical, Wikipedia 0.02 sec.
Protostomia [‚prōd·ə′stō·mē·ə]
(invertebrate zoology)
A major division of bilateral animals; includes most worms, arthropods, and mollusks.
Protostomia 

a group of invertebrates, including Plathel-minthes, Nemathelminthes, Nemertini, Annelides, Mollusca, and Arthropoda. Protostomes are bilaterally symmetrical animals. Their development is characterized by the formation of a mouth from the primitive blastopore or from its anterior part. The anal opening emerges from the posterior part of the body. There is an exoskeleton of cuticle, chitin, or shell. The foregut and hindgut develop by invagination of the ectoderm. Blastulation is spiral unless it has undergone a secondary change.
How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content.
?Page tools
Printer friendly
Cite / link 		Feedback
Mentioned in?  References in periodicals archive?   Encyclopedia browser?   Full browser?
No references found
 
Eyes appear in the bilaterally symmetrical animals in the protostome invertebrate branch, including the Phylum Arthropoda (jointed leg animals), Annelida (segmented worms), and Mollusca (bivalves, snails, and cephalopods).
Evolution: do the eyes have it? by Reinbold, Stephen L. / Forum on Public Policy: A Journal of the Oxford Round Table
Lophotrochozoa: A Major Branch of Life Unexplored Bilateral symmetry is found in 3 major clades of animals: the Deuterostomes (which includes vertebrates) and two clades of Protostomes, the Ecdysozoa (which includes arthropods and nematodes) and the Lophotrochozoa (which includes molluscs and annelids).
The case for sequencing the Pacific oyster genome by Warr, Gregory W. / Journal of Shellfish Research
 
 
 
Encyclopedia
?

Terms of Use | Privacy policy | Feedback | Copyright © 2012 Farlex, Inc.
Disclaimer
All content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional.