It is probably owing to this story about their origin, that Eustathius describes them as marine beings without feet, the place of the hands being occupied by fins, though in the same page he also states that originally they were the dogs of Actaeon, who were changed into men.
The accounts of the Telchines are very few and scanty, and in them they appear in three different relations:
1. As cultivators of the soil and ministers of the gods; and as such they came from Crete to Cyprus and from thence to Rhodes, or they proceeded from Rhodes to Crete and Boeotia. Rhodes, and in it the three towns of Cameirus, lalysos, and Lindos (whence the Telchines are called lalysii: Metamorphoses by Ovid VII), which was their principal seat and was named after them, (Sicyon also was called Telchinia) was abandoned by them, because they foresaw that the island would be inundated, and thence they scattered in different directions: Lycus went to Lycia, where he built the temple of the Lycian Apollo.
Poseidon was intrusted to them by Rhea, and they in conjunction with Capheira, a daughter of Oceanus, brought him up. Rhea, Apollo and Zeus, however, are also described as hostile to the Telchines for Apollo is said to have assumed the shape of a wolf and to have thus destroyed the Telchines and Zeus is said to have caused their destruction by an inundation (Metamorphoses by Ovid VII).
2. As sorcerers and envious daemons. Their very eyes and aspect are said to have been destructive. They had it in their power to bring on hail, rain, and snow, and to assume any form they pleased; they further mixed Stygian water with sulphur, in order thereby to destroy animals and plants.
3. As artists, for they are said to have invented useful arts
and institutions and to have made images of the gods. They worked
in brass and iron, made the sickle of Cronos and the trident of Poseidon. This last
feature in the character of the Telchines seems to have been the
reason of their being put together with the Idaean Dactyls, and Strabo even states that those of
the nine Rhodian Telchines who accompanied Rhea to Crete, and
there brought up the infant Zeus, were called Curetes.
From Dionysiaca by Nonnus
"The spiteful Telchines also came also to the Indian War, gathering out of the cavernous deeps of the sea. Lycos came, shaking with his long arm a very long spear; Scelmis came, following Damnameneus, guiding the seachariot of his father Poseidon. These were wanderers who had left Tlepolemos’s land and taken to the sea, furious Demons of the waters, who long ago had been cut off from their father’s land by Thrinax with Macareus and glorious Auges sons of Helios; driven from their nursing-mother they took up the water of Styx with their spiteful hands, and made barren the soil of fruitful Rhodes, by drenching the fields with water of Tartaros.”
From The Chronology Of Ancient Kingdoms Amended.
1045. Many of the Phnicians and Syrians fleeing from Zidon and from David, come under the conduct of Cadmus, Cilix, Phnix, Membliarius, Nycteus, Thasus, Atymnus, and other Captains, into Asia minor, Crete, Greece, and Libya; and introduce Letters, Music, Poetry, the Octaeteris, Metals and their Fabrication, and other Arts, Sciences and Customs of the Phnicians. At this time Cranaus the successor of Cecrops Reigned in Attica, and in his Reign and the beginning of the Reign of Nyctimus, the Greeks place the flood of Deucalion. This flood was succeeded by four Ages or Generations of men, in the first of which Chiron the son of Saturn and Philyra was born, and the last of which according to Hesiod ended with the Trojan War; and so places the Destruction of Troy four Generations or about 140 years later than that flood, and the coming of Cadmus, reckoning with the ancients three Generations to an hundred years. With these Phnicians came a sort of men skilled in the Religious Mysteries, Arts, and Sciences of Phnicia, and settled in several places under the names of Curetes, Corybantes, Telchines, and Idæi Dactyli.