Sense globe
From Tardis Wiki, the free Doctor Who reference
According to the pamphlet, "Anatomy of the Dalek", sense globes dotted the lower half of the frame of Daleks. (COMIC: City of the Daleks) Other sources sometimes called these parts of a Dalek casing sensor globes. (PROSE: War of the Daleks, Remembrance of the Daleks)
Though these globes were typically arranged in even rows that flared out slightly as they radiating down the body, arrangement was not uniform across all Daleks. The Marine Dalek, for instance, had a different configuration than standard Daleks. (PROSE: War of the Daleks)