William Talvas may refer to three Franco-Norman magnates:

• William I Talvas (c. 995–after 1030), seigneur of Alençon
• William III of Ponthieu (c. 1095–1172), aka William II Talvas, son of Robert II of Bellême and Agnes of Ponthieu
• William IV of Ponthieu (1179 – 1221), William III Talvas, Count of Ponthieu and William IV of the house of Belleme/Montgomery

• Mutatis mutandis (disambiguation)
• Mutatocoptops alboapicalis
• Mutatocoptops albosparsa
• Mutatocoptops anancyloides
• Mutatocoptops annulicornis
• Mutatocoptops bituberosa
• Mutatocoptops borneensis
• Mutatocoptops cambodgensis
• Mutatocoptops celebensis
• Mutatocoptops diversa
• Mutatocoptops lumawigi
• Mutatocoptops malaisiana
• Mutatocoptops nigrosparsa
• Mutatocoptops purpureomixta
• Mutatocoptops robustipes
• Mutatocoptops rufa
• Mutatocoptops salvazai
• Mutatocoptops salwazei
• Mutatocoptops similis
• Mutatocoptops tonkinea
• Mutatocoptops vitalisi
• Mutat. Res. Fundam. Mol. Mech. Mutagenesis
• Mutat Res Fundam Mol Mech Mutagenesis
• Mutat Res Genet Toxicol Environ Mutagenesis
• Mutat. Res. Genet. Toxicol. Environ. Mutagenesis