Equidae
Equidae (sometimes known as the horse family) is the taxonomic family of horses and related animals, including the extant horses, donkeys, and zebras, and many other species known only from fossils. All extant species are in the genus "Equus". Equidae belongs to the order Perissodactyla, which includes the extant tapirs and rhinoceros, and several extinct families.
Canadia (annelid)
There has been some debate as to the placement of "Canadia" within the Annelida phylum. Although it is commonly accepted to be within Annelida, it is uncertain how it relates to modern annelids. Most paleontologists agree that it belongs to the class Polychaeta due in part to the presence of Parapodium. It has been proposed to be a member of the order Phyllodocida along with "Wiwaxia", another organism from the Burgess Shale. Both were placed in a new superfamily called Canadiacea, and were thought to be of closer relationship to each other than to modern annelids. However, "Wiwaxia" is no longer believed to have been an annelid and there is currently dispute as to whether or not "Canadia" should be classified as belonging to anything more derived than Polychaeta.