O best of men, know that there are seven classes of Pitris, of which four classes have embodied forms, the three remaining classes have no forms.
पितॄणां च गणान् विद्धि सप्तैव पुरुषर्षभ। मूर्तिमन्तो हि चत्वारस्त्रयश्चाप्यशरीरिणः॥