Round piece is disk-shaped macehead, of hornblende diorite, # 10.130.1207
Flint Fishtail Blades
Naqada I to Naqada II (3900 - 3330 BCE) Obsidian Fishtail Blade
Naqada III- Dynasty 1 (3300 - 2900 BCE)
Photo of info card,
Also see link to museum view of second blade,# 07.228.162, its edge is serrated.
The museum also has a photo of the fourth blade # 10.130.1222
"Fishtail blades are distinctive flint shapes found principally in burials
throughout the Predynastic Period. Although the blade's upper portion is
skillfully edged with tiny saw-like teeth, the V-shaped edge is the cutting
surface. Currently, scholars believe that these blades are an early form of
the adze-like implement used in the Opening-of-the-Mouth ceremony, part
of the funeral ritual in Pharaonic times. The fishtail blade's exact function
in the Predynastic Period is unknown, but as many are found in excellent
condition, a ceremonial use is suspected."|
The Metropolitan has a miniature Opening of the Mouth tool set, whereby we can see the similarity of the fishtail with the peshkent knife.