Definition: A group of hydrous aluminium phyllosilicate (phyllosilicates being a subgroup of silicate minerals) minerals (see clay minerals), that are typically less than 2micrometres in diameter. Clay consists of a variety of phyllosilicate minerals rich in silicon and aluminium oxides and hydroxides which include variable amounts of structural water.
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/
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/
Definition: Because of the difference in refractive index between air and water (or corneal tissue), a curved cornea is an image-forming lens in its own right. Its focal length is determined by the radius of curvature of the cornea. Many corneal eyes (eg: in land vertebrates) also have lenses, but the lens is flattened and weakened compared with an aquatic lens; most of the refractive power is provided by the cornea. Corneal eyes cannot focus in aquatic habitat.
