Slat

Slats (PROSE: Prisoner of the Daleks) studded the weapons platform of the casings of most Daleks. (TV: Genesis of the Daleks, The Chase)

Dalek X, the Dalek Inquisitor General, was distinguished by his black casing with golden slats and sense globes. (PROSE: Prisoner of the Daleks)

Behind the scenes
The Daleks seen in the theatrical film Daleks' Invasion Earth 2150 A.D. (held to be an invalid source by this Wiki) all had silver slats regardless of the colour of their wider casing.