Colours Animals See
Animals have been used to create vaccines since their discovery within the 18th century. Some medicines such as the most cancers drug Yondelis are based on toxins or different molecules of animal origin. This division into 4 was adopted by the embryologist Karl Ernst von Baer in 1828, the zoologist Louis Agassiz in 1857, and the comparative anatomist Richard Owen in 1860. The Lophotrochozoa consists of the molluscs, annelids, brachiopods, nemerteans, bryozoa and entoprocts. The molluscs, the second-largest animal phylum by number of described species, includes snails, clams, and squids, while the annelids are the segmented worms, similar to earthworms, lugworms, and leeches.