Definition: Pseudocleavage begins just as the oocyte and sperm pronuclei appear at the anterior and posterior poles, respectively, of the elongated embryo. During this process, waves of cortical contraction sweep from posterior to anterior, and eventually become confined to the anterior membrane. A single large constriction, known as the pseudocleavage furrow, forms and subsequently regresses
Definition: A taxon is Vulnerable when the best available evidence indicates that it meets any of the criteria A to E for Vulnerable, and it is therefore considered to be facing a high risk of extinction in the wild.
Definition: Peabody Museum of Natural History (YPM). New Haven, Connecticut, USA. The Yale Peabody Museum's collections are available to legitimate researchers for scholarly use. Loans are issued to responsible individuals at established institutions. Loans and access to the collection can be arranged through the Collections Manager of the appropriate Division. http://www.peabody.yale.edu/collections/index.html , URL for main institutional website, http://www.peabody.yale.edu/