'प्रजा ह तिस्रो अत्यायमीयुरिति या वै ता इमाः प्रजाः तिस्रोऽत्यायमीयुस्तानीमानि वयांसि वङ्गा वगधाश्चेरपादाः' इति श्रुतम् ।वङ्गा वनगाः वृक्षाः ।वगधाः ओषधयश्च ।इरपादा उरःपादाः सर्पादयः ।तथा च ईशावास्ये अविद्वन्निन्दार्थो मन्त्रः— 'असुर्या नाम ते लोका अन्धेन तमसा वृताः ।ताँस्ते प्रेत्याभिगच्छन्ति ये के चात्महनो जनाः' इति ।'असन्नेव स भवति ।असद्ब्रह्मेति वेद चेत्' इति तैत्तिरीये ।तथा शाकुन्तलोपाख्याने— 'योऽन्यथा सन्तमात्मानमन्यथा प्रतिपद्यते ।किं तेन न कृतं पापं चोरेणात्मापहारिणा ॥' इत्यलमतिप्रसङ्गेन ॥सहस्रनामजपस्य अनुरूपं मानसस्नानमुच्यते—
In plain words
As scripture declares: 'Three progeny went astray by transgressing—namely, birds, tree-dwellers like Vangas, plants like Vagadhas, and crawling serpents.' Similarly, the Isha Upanishad rebukes the ignorant: 'Those worlds are sunless, shrouded in utter darkness; to them go all those who deny their own Self after death.' And the Taittiriya states: 'He becomes as if non-existent if he regards Brahman as non-existent.' Likewise, the Shakuntala episode warns: 'Whoever misconceives his own existing Self, what terrible sin is left undone by such a thief who robs his own soul?' Enough of this extensive elaboration.
Close to the Sanskrit
It is heard in scripture: 'That three progeny transgressed and went away—these are birds, Vangas, Vagadhas, and footless/chest-footed ones.' Vangas are forest-goers, trees. Vagadhas are herbs. Chest-footed ones are serpents and others. Similarly, in the Ishavasya, there is a mantra intended to censure the ignorant: 'Sunless are those worlds, covered by blind darkness; to them go after death those people who are slayers of the Self.' 'He becomes as if non-existent, if he knows Brahman as non-existent,' in the Taittiriya. Likewise in the Shakuntala episode: 'Whoever conceives his existing Self otherwise, what sin is not committed by him, a thief who steals the soul?' Enough of excessive elaboration.