| S.N | Acraniata | Craniata |
| 1. | They are exclusively marine. | They are aquatic or terrestrial. |
| 2. | They are small sized chordates. | They are mostly large sized vertebrates. |
| 3. | Appendages, cephalization and exoskeleton are absent. | Appendages are two pairs usually, well developed head and exoskeleton present. |
| 4. | Coelom is enterocoelic, budding off from embryonic archenteron. | Coelom is schizocoelic, arising by splitting of mesoderm. |
| 5. | Notochord persistent. | Notochord is not persistent i.e. covered or replaced by vertebral column. |
| 6. | Skull, cranium and vertebral column are absent. | Skull and cranium well developed. |
| 7. | Pharynx with permanent gill clefts. | Pharyngeal gill clefts persist or disappear. |
| 8. | Endostyle is present. | Endostyle is absent. |
| 9. | Heart chambers less when present. | Heart made of 2, 3, or 4 chambers. |
| 10. | Red blood corpuscles in blood are absent. | Blood contains RBC. |
| 11. | Kidneys are protonephridia. | Kidneys are meso or metanephridia. |
| 12. | Sexes are separate or united, reproduction asexual. | Sexes are separate. Only sexual reproduction. |
| 13. | Gonoducts usually absent. | Gonoducts always present. |
| 14. | Development is indirect with a free swimming larval stage. | Development is indirect or direct, with or without a larvae stage. |
References:
i) https://www.differencebetween.com/difference-between-acrania-and-craniata/
ii) https://www.topperlearning.com/answer/hi-distinguish-between-acrania-craniata/3091