I recently took in a stray or abandoned two year old cat and
need to trim his claws. He is very friendly and allows me to
handle his paws and extend his claws, so I hope he is also
accustomed to having his claws clipped. All that I have read
cautions not to cut the "quick" since it contains nerves and
blood vessels, but sources differ in describing it. Some say
it is the pink part forming the base of the claw; others say
it is a dark or pink crescent-shaped area within the claw.
Which is it? Or are they the same?

Both of these parts are visible in the photo:
http://www.caws.org/extended.html
It shows the quick as the pink base and the cut-line
passing through the dark crescent. According to some sources
this is exactly what not to do (?).

A similar photo:
http://www.maxshouse.com/anatomy/claws/Claw-trim-quick-1.jpg

These pages show the quick as the dark/pink crescent:
http://www.cat-world.com.au/catclaws.htm
http://tinyurl.com/43mcn

I cannot see the crescent in my cat's paws, except for
a small area next to the pink base. But I can see a fine
line in the claw running from the base to almost the end.
Perhaps I am mistaken, and the line is a crack or surface
feature, but don't want to cut it in case it is the quick.

Obviously I'm new at this and don't want to cause any pain
or fear in the cat. Please help me identify the quick and
where to clip. Thanks.