AmebocyteAn amebocyte or amoebocyte (/əˈmiː.bə.saɪt/) is a mobile cell (moving like an amoeba) in the body of invertebrates including cnidaria, echinoderms, molluscs, tunicates, sponges and some chelicerates. They move by pseudopodia. Similarly to some of the white blood cells of vertebrates, in many species amebocytes are found in the blood or body fluid and play a role in the defense of the organism against pathogens. Depending on the species, an amebocyte may also digest and distribute food, dispose of wastes, form skeletal fibers, fight infections, and change into other cell types.
AmbulacrariaAmbulacraria ,aembjuːl@'krɛəri@, or Coelomopora siːl@'mQp@r@, is a clade of invertebrate phyla that includes echinoderms and hemichordates; a member of this group is called an ambulacrarian. Phylogenetic analysis suggests the echinoderms and hemichordates separated around 533 million years ago. The Ambulacraria are part of the deuterostomes, a larger clade that also includes the Chordata, Vetulicolia. The two living clades with representative organisms are: Echinodermata (sea stars, sea urchins, brittle stars, sea cucumbers, feather stars, sea lilies, etc.
SpermathecaThe spermatheca (pronounced spɚməˈθiːkə plural: spermathecae spɚməˈθiːsiː), also called receptaculum seminis (plural: receptacula seminis), is an organ of the female reproductive tract in insects, e.g. ants, bees, some molluscs, oligochaeta worms and certain other invertebrates and vertebrates. Its purpose is to receive and store sperm from the male or, in the case of hermaphrodites, the male component of the body. Spermathecae can sometimes be the site of fertilization when the oocytes are sufficiently developed.
