Four ivory netsuke of monkeys

Four ivory netsuke of monkeys
Edo period (1615-1868), 19th century
The first a monkey seated, holding a mushroom, the pupils inlaid, unsigned, 3.8cm (1½in) high; the second a young ape crouching, its head turned to the right and the eyes inlaid, unsigned, 3.5cm (1 3/8in) wide; the third a monkey carrying a huge mushroom and balancing on one foot, unsigned, 6.5cm (2 5/8in) high; the fourth the Sanbiki no Saru (Three Mystic Apes), inscribed Minkoku, 2.5cm (1in) high. (4).