🧬🪱📚

#annelid phylum #zoology #invertebrate biology #worm study #annelid classification

🪱🪝🦠

#scolex #tapeworm #cestode #helminth #attachment organ #worm head #invertebrate biology

🚫🦴🧬

#no backbone #spineless animal #biological classification #invertebrate biology #animal anatomy #vertebrate contrast #animal kingdom structure