The family Acarnidae is characterized by sponges with ectosomal diactinal spicules and choanosomal monactinal spicules. Microscleres include palmate isochelae, toxas and echinating acanthostyles. We described ten species from the Mexican Pacific Ocean. Six of them are new to science: Acarnus michoacanensis n. sp., Acarnus oaxaquensis n. sp., Acarnus sabulum n. sp., Acheliderma fulvum n. sp., Megaciella toxispinosa n. sp. and Iophon bipocillum n. sp. Four are known in Eastern Pacific waters: Acarnus erithacus, Acarnus peruanus, Megaciella microtoxa and Iophon indentatum.