Dodatak:Popis prakliještara, M

Meg

, Megalograptidae Caster & Kjellesvig-Waering, 1955 † , Megalograptoidea Caster & Kjellesvig-Waering, 1955 † , Megalograptus Miller, 1874 † , Megarachne Hunicken, 1980 †

Mel

†Melbournopterus Caster & Kjellesvig-Waering, 1953

• †Melbournopterus crossotus Caster & Kjellesvig-Waering, 1953

Animalia → Arthropoda → Merostomata → Eurypterida → Stylonuridae

Mer

Razred Merostomata Woodward, 1866

1. Xiphosurida R. & E. Richter, 1924
2. Aglaspida Walcott 1911
3. †Angarocaris
4. †Borchgrevingkium
5. †Eolimulus Bergström 1968
6. †Flobertia
7. †Gdowia
8. †Girardevia
9. †Kodymirus
10. †Maldybulakia Tesakov and Alekseev 1998
11. †Sinaglaspis
12. †Triopus
13. †Tuboculops
14. †Willwerathia

Animalia → Arthropoda → Chelicerata

Mes

, Mesolimulinae Størmer, 1952 † , Mesolimulus †

Mi

, Mixopterus

Mo

, Moravuridae Pribyl, 1967 † , Moselopterus

My

, Mycteropidae , Mycterops Cope, 1886 † , Mycteroptidae Cope, 1886 †