RYE, N.Y. -- A black scottie with a silk scarf around its neck walks on a long leash through the lobby of the Rye Hilton. On the mezzanine, menswear makers push everything from Grecian Formula to Stetsons, and the smell of men's cologne is overpowering. Male models, in between shows, have changed out of the cashmere topcoats, shearling jackets and pleated wool jersey trousers they wore in the 1987 Men's Fashion Association fall shows this week. In their own worn-out blue jeans and political propaganda T-shirts, they congregate in corners and joke around -- their runway scowls and pouts have been abandoned, too. Merchandisers and designers shoot the breeze in garmento slang: "What's the price point of your line?"

Other than dollars and cents, there was no dominant topic of conversation this week at the MFA, an association of more than 400 menswear manufacturers and designers. There was no astounding fashion development, no major breakthrough in business suits, no equivalent to the swift and shocking changes that occur in womenswear. It's a new season, like any new season, and the shifts are subtle.

Jacket lapels are back, much wider and notched. Shirts are cut fuller -- five more inches at stodgy Van Heusen, where spread collars are spread still farther apart. Trousers, although pleated and very baggy at the hips, are slimmer in the leg and most noticeably at the ankle. The trendiest -- Kermit Smith's for Krunch, for example -- are long with a full break at the cuff. At Bill Robinson, pants are pleated but made of stretch jersey and fit nearly like ski pants below the thigh. The "Reagan browns" of the last few years have gone gray. Conservatives can rest easy, though, for charcoal and navy are still in the majority.

Jacket silhouettes show the most change, bigger in the chest, tighter in the waist. Men will have to stand up straighter now that the shoulders are becoming more slouchy. The semiconstructed jackets have slightly padded shoulders that slump nearly off the shoulders. (Remember the jacket Willi Smith designed for the Ed Schlossberg/Caroline Kennedy wedding last summer? You're getting the picture.) This limp, lazy-looking shoulder has shown up everywhere so far -- at Ronaldus Shamask, Jeff Sayre, Kermit Smith for Krunch and Bill Robinson. Many have '40s styling details, such as wide, notched lapels or a belted back.

These may sound like terribly trendy innovations to those who shop solely at Brooks Brothers, but to the fashion buyers and press here they are hard-won changes.

Between shows, all held conveniently in the same ballroom of the hotel, the crowd browses the MFA sideshows. Surrounding the ballroom are booth-lined arcades promoting socks, shoes, shampoo-in hair color, hats, jewelry. Next to a display of Bill Blass braided leather braces (not suspenders -- they're elastic) is the Western Boot Council of America booth, offering ostrich, snakeskin, lizard, elephant and sharkskin boots. Several vintage pairs sit next to a television playing a documentary on the history of the cowboy boot.

"It's been a gradual evolution," says Barbara Lewis, the WBCA rep. "It's almost stayed the same since the 1800s." The toes are pointy in order to find the stirrups more quickly, she says, and western boot makers have long been attracted to exotic skins. The angled, stacked heels are for digging into the terrain while roping steer.

Any changes in cowboy boots this year? "There is a return to a shorter shaft that was used at the turn of the century," she says, holding out a squat pair of black boots with magenta and orange embroidery. "And the stitching is much more elaborate."

Across the arcade are displays of printed boxer shorts -- a popular item that women are buying like hotcakes for themselves as well as for men. One company, Joe Boxer, shows shorts printed with big yellow bananas alongside a coonskin cap, boxing gloves and a coronation portrait of Queen Elizabeth.

Inside the ballroom the shows go on, one right after the other. Some of the best collections were seen Thursday morning at the MFA's Designer Portfolio -- a sampling of several shows.

Krunch by Kermit Smith is a sleek, avant-garde collection, the highlight of which was a short, swingy coat in gray fuzzy wool paired with black knit pants and a blaring red crew-neck sweater.

Shamask showed his usual luxurious menswear -- superlong cashmere topcoats and a wonderful black and white houndstooth jacket with an elasticized back, which is becoming one of his trademark details. At Shamask the clothes were rarely shown with neckties. Dark knit wool polo shirts, buttoned to the chin, were worn underneath jackets or zip-up cashmere turtlenecks.

Washingtonians may be interested to know that Robert Peritz's casual collection, shown all at once, is called "Georgetown." The four models came out not only wearing the line but carrying various yuppie accouterments -- a squash racket in a tote bag, dry cleaning still wrapped in plastic, a bag of groceries. One model, carrying a brown saddlebag, wore a distracting electric-green corduroy jacket that looked as if it more properly belonged wadded up in a corner and soaked in beer while its owner was on the dance floor gatoring.

Bill Ditfort, who has done some sweater designing for the Britches label, got a round of applause for a line of brightly colored "Snoopy" sweaters. One called "Snoopy on the doghouse" featured the famous Peanuts character asleep on the roof. The greatest cheer went to Cecilia Metheny, a newcomer to menswear, who ended the showing of her first collection with a very long dressing gown in thick silk-satin, fittingly printed in a peacock feather pattern.

Bill Robinson -- who designed for Calvin Klein menswear for six years and for Yves Saint Laurent for two, and who won the Cutty Sark Menswear Award as Most Promising Designer 1987 on Thursday night -- came up with some inventive scrambled classics for his second fall collection. He showed a charcoal-gray sweater and sport coat with navy-blue trim, stolen from a Chesterfield coat, and traditional double-breasted suit coats turned into short, waist-length jackets. Last year, his short jacket was a redone "Eisenhower"; this year's is almost a Spencer, with very wide lapels -- "at least four inches," Robinson says. All the jackets and coats in his collection were a little skimpy in length, the topcoats hitting at or above the knee.

Robinson keeps trying to tone down his tendency to be daring. It doesn't pay in menswear, he says. "Last fall I had a much more exaggerated silhouette. This year I've tried to bring it in a little bit, adapt it, to make the clothes more wearable ... to where people are not afraid of them."

Mixing old styles in new ways is part of the formula for success at which Robinson excels. He showed his dressy dark pin-stripe suits with '60s-style mock turtlenecks -- he describes his collection, which will be sold in Washington at Woodward & Lothrop, as "sort of Wall Street meets the Beatles."

Although the dressed-up but tieless look is clearly one of the messages of the MFA this fall, Robinson still likes to show about half of his outfits with ties. "A tie," he says, "is an area where a man will take a risk."

After the shows, the crowds fill the corridors again. One blond man in a baggy suit experiments with an exercise bike brought by a men's fragrance company. Another sits in a barber's chair set up in the hallway. "This isn't so bad -- yet," he says, as a green herbal mask is applied to his face. And the black scottie walks by, this time in a new scarf.