The Grihya Sutras, Part 1 (SBE29), by Hermann Oldenberg, , at sacred-texts.com
1. In the fourth month of pregnancy the Sîmantonnayana (or parting of the hair, is performed).
2. In the fortnight of the increasing moon, when the moon stands in conjunction with a Nakshatra (that has a name) of masculine gender
3 3. Then he gives its place to the fire, and having spread to the west of it a bull's hide with the neck to the east, with the hair outside, (he makes oblations,) while (his wife) is sitting on that (hide) and takes hold of him, with the two (verses), 'May Dhâtri give to his worshipper,' with the two verses, 'I invoke Râkâ' (Rig-veda II, 32, 4 seq.), and with (the texts), 'Negamesha,' and, 'Pragâpati, no other one than thou' (Rig-Veda X, 121, 10).
4. He then three times parts her hair upwards (i.e. beginning from the front) with a bunch containing an even number of unripe fruits, and with a porcupine's quill that has three white spots, and with three bunches of Kusa grass, with (the words), 'Bhûr bhuvah, svar, om!'
5. Or four times.
6. He gives orders to two lute-players, 'Sing king Soma.'
7 7. (They sing) 'May Soma our king bless the human race. Settled is the wheel of N.N.'(here they name) the river near which they dwell.
8. And whatever aged Brâhmana woman, whose husbands and children are alive, tell them, that let them do.
9. A bull is the fee for the sacrifice.
181:3 14, 3. Comp. above, chap. 8, 9. Regarding the two verses Dhâtâ dadâtu dâsushe, see Sâṅkh.-Grihya I, 22, 7. The Negamesha hymn is Rig-veda Khailika sûkta, vol. vi, p. 31, ed. Max Muller.
181:7 Comp. Pâraskara I, 15, 8. The Gâthâ there is somewhat different. I cannot see why in the Âsvalâyana redaction of it nivishtakakrâsau should not be explained, conformably to the p. 182 regular Sandhi laws, as nivishtakakrâ asau. The wheel of course means the dominion.