System Glossary
 Glossary Search for spectacle (Search Options)

Definition of Term

(English) A transparent membrane covering the eye. Petromyzontidae have a primary spectacle that is an unattached modification of the cornea while other fishes may have a secondary spectacle formed from skin originally fused to the cornea and subsequently separated. The secondary spectacle is found in fish that live in habitats with abrasive substrates or in fish with protruding eyes that require some streamlining.

Other Search Engines

European Environment Agency Glossary of the European Environmental Agency
Wikipedia The Free Encyclopedia
Encyclopedia Britannica Highly authoritative source
EPA Terms Glossary of the U.S. Environmental Protection Agency
Google Search The largest Internet Search Engine
Google Image Search for Images related to the term
eENVplus Thesaurus Thesaurus gathering glossaries for biodiversity, environment and biogeography
A-Z Biodiversity Terms Glossary providing definitions of terms, areas and acronyms related to biodiversity, commonly used, internationally recognized where possible, well referenced, and derived from legitimate sources
Glossary Index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Back to Search
Back to Top