or SINNIS (Σίνις or Σιννις), a son of Polypemon, Pemon or Poseidon by Sylea, the daughter of Corinthus. He was surnamed according to some Pityocamptes, and according to others Procrustes. He dwelt on the isthmus of Corinth as a robber, destroying the travellers whom he had conquered, by fastening them to the top of a fir-tree, which he curbed, and then let spring up .gain. He himself was killed in this manner by Theseus (Apollod. 3.16.2; Plut. Thes. 8; Paus. 2.1.3, &c.; Diod. 4.59 ; Eur. Hipp. 977; Ov. Met. 7.440, &c. ; Hyg. Fab. 38; Schol. Pind. Hypoth. Isthm.). When Theseus had accomplished this, he caused himself to be purified by Phytalus at the altar of Zeus Meilichios, because Theseus himself was related to Sinis (Paus. 1.37.3), or according to others, he propitiated the spirit of Sinis by instituting in his honour the Isthmian games (Schol. Pind. l.c. ; Plut. Thes. 25; Welcker, Nachtrag, p. 133). The name is connected with σίνομαι, expressing the manner in which he tore his victims to pieces.