Shiva Purana
अन्तःप्रकाशास्तिर्यंच आवृताश्च बहिः पुनः ॥ पश्वात्मानस्ततो जाता उत्पथग्राहिणश्च ते ॥ ७ ॥
These animals had light within but not without. They had the form of animals and went a wrong path.
english translation
antaHprakAzAstiryaMca AvRtAzca bahiH punaH ॥ pazvAtmAnastato jAtA utpathagrAhiNazca te ॥ 7 ॥
hk transliteration by Sanscript