Jala-hatthapada is one of the thirty-two characteristics of a great man like the Buddha. In Northern Buddhism, it implies that He had membranes/webs between the digits of His hands and feet.
However, Buddhaghosa's commentaries refute this idea. Buddhaghosa argues that under the rule of the Vinaya, such a man cannot become even a monk. Moreover, the commentaries explain that the lines formed by the digits and their knots in the great man appear like nets.
Some scholars argued this matter and concluded that the idea of webbed digits emanated from a misinterpretation of the sculptures of the Buddha, whose digits were connected by sculptors to prevent them from fracturing.
In this paper, I attempt to demonstrate that the idea of webbed digits originates from the Sarvastivada school. The evidence is as follows. The word “hamsa-raja” (the king of ganders) appears as a simile of jalini-panipada (=jala-hatthapada) in a Sanskrit scripture, namely, the Mahavadana-sutra, and in the Chinese versions of other sutras; all of these were disseminated by the same school. Moreover, I found pictures of two sculptures with webbed digits, probably carved between the 2nd and 3rd centuries in Mathura, where the Sarvastivada school was influential.