Hrmmm....here's an article I think you might find interesting (stuff in bold is copied and pasted from http://www.hdw-inc.com/spayneuter.htm).

THE NEUTER OPERATION (MALES)

Another name for the neuter surgery performed on male cats is "castration."

Male cats are usually neutered between 5 1/2 and 9 months of age, before habits such as spraying urine are started. Neutering involves the removal of the source of sex hormones and sperm cells, which is the testicles. The two incisions are usually so small that stitches or sutures are not even needed. And, normally, the cat is sent home the very same day.

NEUTERING VS. VASECTOMY IN MALES

There is another procedure available for preventing fertility in males, and that is a "vasectomy". While a vasectomy renders a male cat sterile, it does not affect testosterone levels as long as the spermatic artery is kept intact. A vasectomized cat, in other words, can mate, but cannot father kittens. This procedure is rarely used for domestic male cats, because a vasectomized male cat would still have territorial issues, still perhaps be prone to fighting other cats to protect that territory, still wander and try to get outside in search of a mate, and still spray urine that has a very strong odor. Vasectomy is still a valid alternative for population control in feral cat colonies, however.

Is it possible Remus had a vasectomy or something like that? Since "neutering" is defined as actual removal of the "bits" - castration?

I don't know but I searched for "neutering procedure cats" in Google and this is all I found that had anything to do with alternatives to neutering. Also, there's a site: http://www.geocities.com/catcare2000/neut.htm that actually has before and after drawings of the internal organs of the cat.

Also, I had Tito neutered, and it looks like he still has a little something left there, like a tomcat but smaller "bits." Heck I don't know, who on here is a vet??