Manava Dharmashastra 1.43

1.43

ete jarāyujāḥ | jarāsurulvaṃ garbhaśayyā | tatra prathamaṃ te sambhavanti | tato muktā jāyante | eṣa eteṣāṃ janmakramaḥ | dantaśabdasamānārtho datśabdo'nyo'stītyubhayatodata iti prathamābahuvacane rūpaṃ yujyate |

Medhātithi’s commentary (manubhāṣya):
These are ‘viviparous,’ ‘born from the Jarāyu’; Jarāyu is the womb, the place where the fœtus lies; it is in the womb that these beings are conceived first, and it is only when they are emitted from the womb that they become born; this is the manner of the birth of these beings.

The term ‘dat’ is synonymous with ‘danta,’ and is totally different from it; hence it is that we have the nominative plural form ‘ubhayatodataḥ’ (‘with two rows of teeth’).—(43)