Mahabharata 9.37.32

9.37.32

vāyuvego vāyubalo vāyuhā vāyumaṇḍalaḥ |
vāyujvālo vāyuretā vāyucakraśca vīryavān |
evamete samutpannā marutāṃ janayiṣṇavaḥ || 32 ||

And because the seven mingled together at that spot, therefore is that tirtha known on Earth by the name of Sapta Sarasvati. Thus have I told thee of the seven Sarasvatis, according to their names. I have also told thee of the sacred tirtha called Sapta Saraswat. Listen now to a great feat of Mankanaka, who had from his youth led the life of a brahmacari. While employed in performing his ablutions in the river, he beheld (one day), O Bharata, a woman of faultless limbs and fair brows, bathing in the river at will, her person uncovered. At this sight, O monarch, the vital seed of the Rishi fell unto the Sarasvati. The great ascetic took it up and placed it within his earthen pot. Kept within that vessel, the fluid became divided into seven parts. From those seven portions were born seven Rishis from whom sprang the (nine and forty) Maruts. The seven Rishis were named Vayuvega, Vayuhan, Vayumandala, Vayujata, Vayuretas, and Vayuchakra of great energy. Thus were born these progenitors of the diverse Maruts. Hear now a more wonderful thing, O king, a fact exceedingly marvellous on Earth, about the conduct of the great Rishi, which is well known in the three worlds. In days of yore, after Mankanaka had become crowned with success, O king, his hand, on one occasion, became pierced with a Kusa blade. Thereupon, a vegetable juice came out of the wound (and not red blood). Seeing that vegetable juice, the Rishi became filled with joy and danced about on the spot.