ry estates, and a
few of the solitary towers where the matrix mechanics worked alone with
the secret sciences of Darkover, towers of glareless stone which
sometimes shone like blue beacons in the dark.

Kendricks drove the truck which carried the animals, and was amused by
it. Rafe and I took turns driving the other truck, sharing the wide
front seat with Regis Hastur and the girl Kyla, while the other men
found seats between crates and sacks in the back. Once while Rafe was at
the wheel and the girl dozing with her coat over her face to shut out
the fierce sun, Regis asked me, "What are the trailcities like?"

I tried to tell him, but I've never been good at boiling things down
into descriptions, and when he found I was not disposed to talk, he fell
silent and I was free to drowse over what I knew of the trailmen and
their world.

Nature seems to have a sameness on all inhabited worlds, tending toward
the economy and simplicity of the human form. The upright carriage,
freeing the hands, the opposable thumb, the color-sensitivity of retinal
rods and cones, the development of language and of lengthy parental
nurture--these things seem to be indispensable to the growth of
civilization, and in the end they spell _human_. Except for minor
variations depending on climate or foodstuff, the inhabitant of Megaera
or Darkover is indistinguishable from the Terran or Sirian; differences
are mainly cultural, and sometimes an isolated culture will mutate in a
strange direction or remain, atavists, somewhere halfway to the summit
of the ladder of evolution--which, at least on the known planets, still
reckons homo sapiens as the most complex of nature's forms.

The trailmen were a pausing-place which had proved tenacious. When the
mainstream of evolution on Darkover left the trees to struggle for
existence on the ground, a few remained behind. Evolution did not cease
for them, but evolved _homo arborens_; nocturnal, nystalopic humanoids
who lived out their lives in the extensive forests.

The truck bumped over the bad, rutted roads. The wind was chilly--the
truck, a mere conveyance for hauling, had no such refinements of luxury
as windows. I jolted awake--what nonsense had I been thinking? Vague
ideas about evolution swirled in my brain like burst bubbles--the
trailmen? They were just the trailmen, who could explain them? Jay
Allison, maybe? Rafe turned his head and asked, "Where do we pull up for
the night? It's getting dark, an