182. On the other hand

On the other hand (as was pointed out above, 62), the occurrence of ṣ in Sanskrit words is nearly limited to cases falling under this rule: others are rather sporadic anomalies—except where ṣ is the product of ç or kṣ before a dental, as in draṣṭum, caṣṭe, tvaṣṭar: see 218, 221. Thus, we find—

a. Four roots, kaṣ, laṣ, bhaṣ, bhāṣ, of which the last is common and is found as early as the Brāhmaṇas.

b. Further, in RV., áṣa, kaváṣa, caṣā́la, cā́ṣa, jálāṣa, pāṣyà, baṣkáya, váṣaṭ (for vakṣat?), kā́ṣṭhā; and, by anomalous alteration of original s, -ṣāh (turāṣā́h etc.), áṣāḍha, upaṣṭút, and probably apāṣṭhá and aṣṭhīvánt. Such cases grow more common later.

c. The numeral ṣaṣ, as already noted (149 b), is more probably ṣakṣ.