How does the chitraveena differ from the Saraswati veena?

The chitraveena follows the outer form of the fretted Saraswati veena: a hemispherical wooden chamber, usually jackfruit, joined to a hollow stem about 81 cm long. Its three drone-rhythm strings are tuned Sa-Pa-Sa, as on the Saraswati veena. Unlike that veena, it is fretless and played with a slide, and it adds 11 or 12 sympathetic strings below its six melody strings.