name is explained from an incident in the _Tain_, in which the hero,
reproached for his youth, puts on a false beard before attacking
Morrigan in her form as an eel. This is expressed by _smerthain_, "to
attach", and is thus connected with and gave rise to the name
Smertullos. On the altar Smertullos is attacking an eel or serpent.
Hence Pollux is Smertullos-Cuchulainn.[486] Again, the name Cernunnos
signifies "the horned one," from _cernu_, "horn," a word found in
Conall's epithet Cernach. But this was not given him because he was
horned, but because of the angular shape of his head, the angle (_cern_)
being the result of a blow.[487] The epithet may mean "victorious."[488]
On the whole, the theory is more ingenious than convincing, and we have
no proof that the figures of Castor and Pollux on the altar were
duplicates of the Celtic pair. Cernunnos was an underworld god, and
Conall has no trace of such a character.

M. D'Arbois also traces the saga in Gaul in the fact that on the menhir
of Kervadel Mercury is figured with a child, Mercury, in his opinion,
being Lug, and the child Cuchulainn.[489] On another altar are depicted
(1) a woodman, Esus, cutting down a tree, and (2) a bull on which are
perched three birds--Tarvos Trigaranos. The two subjects, as M. Reinach
points out, are combined on another altar at Treves, on which a woodman
is cutting down a tree in which are perched three birds, while a bull's
head appears in the branches.[490] These represent, according to M.
D'Arbois, incidents of the _Tain_--the cutting down of trees by
Cuchulainn and placing them in the way of his enemies, and the warning
of the bull by Morrigan in the bird form which she shared with her
sisters Badb and Macha.[491] Why, then, is Cuchulainn called Esus?
"Esus" comes from a root which gives words meaning "rapid motion,"
"anger," "strength"--all shown by the hero.[492] The altars were found
in the land of the Belgic Treveri, and some Belgic tribes may have
passed into Britain and Ireland carrying the Esus-Cuchulainn legend
there in the second century B.C., e.g. the Setantii, dwelling by the
Mersey, and bearing a name similar to that of the hero in his
childhood--Setanta (_Setantios_) as well as the Menapii and Brigantes,
located in Ireland by Ptolemy.[493] In other words, the divine Esus,
with his surname Smertullos, was called in Ireland Setanta, after the
Setantii, and at a later date, Cuchulainn. The princely name Donnotaurus
resembl