सम्यति before that, द्वितीयम् second, रावणशिरः Ravana's head, सायकैः by arrows, छिन्नम् cut off, तत् that, शीर्षम् head, छिन्नमात्रम् as he cut, पुनरेव again, दृश्यते appeared

Before cutting that second head of Ravana again another head appeared.