Two wood netsuke and three ivory skulls

Two wood netsuke and three ivory skulls
Edo period (1615-1868) or Meiji era (1868-1912), 19th to early 20th century
The first a human skull resting on two human bones, signed Jiro, 6cm (2 3/8in) high; the second a seahorse, the eyes inlaid, unsigned, 6cm (2 3/8in) high; the first of the skulls realistically carved and with a himotoshi, unsigned, 4.2cm (1 5/8in) high; the second an okimono, stained for effect, signed Mitsugetsu, 5.4cm (2 1/8in) high; the third of similar form, unsigned, 3.5cm (1 3/8in) high. (5).