My homepage has links to pages a.html and b.html. In the same directory with these 2 pages, I have pages **c.html** and **d.html** which **are not linked to by any other pages**.

My question is **Do webcrawlers also index c.html and d.html** just because they are in the directory? Or do they only follow the links starting from the home page and index only the homepage plus pages a and b? Thanks.