''When we started in business 13 years ago, floral, shell and fine arts designs were most popular,' said Ann Capuano, the concern's executive vice president and owner. ''There was no interest in cats. Three years ago, we started putting cats on trays, napkins, glasses, coasters and other items. They were so successful we went from one design to two, three, four, then eight.''

Since then, the company has done so well in this product area, she says, that it has become a leading supplier of the cat specialty trade. ''For example, we have a set of coasters with six assorted cats on them,'' she said. ''We now sell about 45,000 of these sets a year.'' She said the company would double its cat-related items in 1991, to about 24. While declining to provide specific numbers, she said that such merchandise accounted for sales ''well into the six figures.''

Ms. Capuano estimated that there were at least 1,000 shops around the country, selling nothing but cat-related items. ''Florida has a ton,'' she said, noting that state's status as a retirement haven.

Paula Gettino, gift specialist for Hallmark Cards in Kansas City, agrees that cats now rank first as design subjects for gift items.

In 1989, Hallmark increased the number of cat-theme products, in selected stores, from 50 to 200. They include mugs, figurines, napkin rings, baskets, jewelry and bookends.

Marilyn Dipboye of Warren, Mich., president of Cat Collectors, an organization of 1,000 people who collect cat-related items, believes buying patterns reflect not only the popularity of cats, but also greater bonding between cats and owners.

Why don't dog-theme items sell as well? One reason, merchandisers say, is that dog people are breed-oriented. A poodle owner, for example, will not buy a German shepherd design. A cat lover, on the other hand, will buy any kind of cute feline depiction.