He grouped what the modern zoologist would call vertebrates as the hotter "animals with blood", and below them the colder invertebrates as "animals without blood".
hiː ɡɹˈuːpt wʌt ðə mˈɑːdɚn zuːˈɑːlədʒˌɪst wʊd kˈɔːl vˈɜːɾɪbɹˌeɪts æz ðə hˈɑːɾɚ "ˈænɪməlz wɪð blˈʌd", ænd bᵻlˌoʊ ðˌɛm ðə kˈoʊldɚɹ ɪnvˈɜːɾɪbɹˌeɪts æz "ˈænɪməlz wɪðˌaʊt blˈʌd".