俱舍論頌疏論本 10.46

10.46

八自二無色者，謂初、二禪緣自界八，謂彼喜、捨各緣四境，除香味四。二無色者，緣無色二，謂喜與捨各緣彼法。

Regarding "eight their own, and two the formless": the first and second dhyānas cognizing their own realm have eight—namely, their joy and equanimity each cognizing four objects, excluding the four of smell and taste. "Two the formless" means cognizing two of the formless realm: joy and equanimity each cognizing its dharmas.