That this girl is a dragon is interesting in itself. In the Indian text she is a naga, the daughter of the Naga King. Along with the garuda, nagas are very commonly found on South East Asian Theravada Buddhist temples. As was the case for most Indian mythical creatures, there were no corresponding mythical creatures in China. The Chinese had no nagas, but they did have dragons, and, both being associated with the sea, that was close enough to suggest translating “naga” into “dragon.” And so it is that in English one sometimes finds this girl referred to as a “Naga Princess.”
The Stories of the Lotus Sutra, p157
Reeves offers this footnote:
Nagas are a kind of sea serpent, often depicted as large king cobras. In Southeast Asia, however, they are thought of as mythical sea serpents and are often depicted a such in Southeast Asian Buddhist temples, usually resembling large snakes more than dragons. But Chinese translators of Buddhist texts did not have nagas in their imaginations. They were, however, quite familiar with dragons, an old symbol of good fortune in China. Thus, typically, naga was translated into lóng, the Chinese word for “dragon.” That is why dragons are so prominent in East Asian Buddhist temples and absent from those in Southeast Asia.
Though repeatedly referred to as a dragon princess, in this story it is as if the girl were human, and, apart from her introduction, that is the way she is treated in the story, and in subsequent Buddhist art. Almost always she is not imagined or depicted as a dragon but as a girl.