俱舍論記 9.76

9.76

「如聖說言至形相滿位」者，答。此明胎內五時次第生長。羯剌藍，此云和合，或云雜穢、或云凝滑。頞部曇，此云皰。閉尸，此云血肉。健南，此云堅肉。盋羅奢佉，此云支節。後髮毛爪等乃至色根形相滿位，總名第五位。若依正量部，髮等已去為第六位。此胎中子處胎之時，如箭入身損害其母，故名胎中箭。

"As the Holy One stated […] the stage when bodily form is complete": the reply. This clarifies the gradual growth through five stages within the womb: Kalala, translated here as harmonious union, or impure mixture, or coagulated slime; arbuda, translated here as blister; peśī, translated here as flesh; ghana, translated here as solid flesh; praśākhā, translated here as limbs and digits. The subsequent stage up to hair, nails, and so forth, until the physical sense faculties and bodily forms are complete, is collectively named the fifth stage. If according to the Sammatīya school, from hair and so forth onward constitutes the sixth stage. When this child in the womb dwells in the womb, it is like an arrow piercing the body, harming the mother; therefore it is called the arrow in the womb.