Sūtra schools (charaṇas), the Çānkhāyanas and the Āçvalāyanas, the former of whom were in later times settled in Northern Gujarat, the latter in the South between the Godāvarī and the Kṛishṇā. The ritual is described in much the same order by both, but the account of the great royal sacrifices is much more detailed in the Çānkhāyana Çrauta Sūtra. The latter, which is closely connected with the Çānkhāyana Brāhmaṇa, seems to be the older of the two, on the ground both of its matter and of its style, which in many parts resembles that of the Brāhmaṇas. It consists of eighteen books, the last two of which were added later, and correspond to the first two books of the Kaushītaki Āraṇyaka. The Çrauta Sūtra of Āçvalāyana, which consists of twelve books, is related to the Aitareya Brāhmaṇa. Āçvalāyana is also known as the author of the fourth book of the Aitareya Āraṇyaka, and was according to tradition the pupil of Çaunaka.
Three Çrauta Sūtras to the Sāmaveda have been preserved. The oldest, that of Maçaka, also called Ārsheyakalpa, is nothing more than an enumeration of the prayers belonging to the various ceremonies of the Soma sacrifice in the order of the Panchaviṃça Brāhmaṇa. The Çrauta Sūtra composed by Lāṭyāyana, became the accepted manual of the Kauthuma school. This Sūtra, like that of Maçaka, which it quotes, is closely connected with the Panchaviṃça Brāhmaṇa. The Çrauta Sūtra of Drāhyāyaṇa, which differs but little from that of Lāṭyāyana, belongs to the Rāṇāyanīya branch of the Sāmaveda.
To the White Yajurveda belongs the Çrauta Sūtra of Kātyāyana. This manual, which consists of twenty-six chapters, on the whole strictly follows the sacrificial
