The Desiderative affix san does not get the augment iṭ , not only after roots ending in 1. u 2. ū 3. ṛ and 4. ṝ but also after graha and guha,
As जिघृक्षति, जुघुक्षति, रुरूषति, लुलूषति ॥ The anuvritti of श्रि is not drawn into this sutra, as option is allowed regarding it by (VII 2. 49). ग्रह would always get इट्, गुह् (1. 944) being ऊदित् (in the Dhatupatha), would have optionally taken इट् 7.2.44
The forms जिघृक्षति and जुघुक्षति are thus evolved :- ग्रह् + सम् (the affix is कित् by 1.2.8) = गृह् + सन् (VI. I. 16) = गृढ् + सन् 8.2.31 = गृक् + सन् 8.2.41 = जिघृक्षति 8.2.37. So also with गुहू संवरणे, the सन् is कित् here by 1.2.10.,