You know about the migration pattern of Manhattanites to Brooklyn. But here’s one swimming against the current.Castor & Pollux, the 4-year-old boutique beloved by stylish Brooklyners, has relocated from Prospect Heights to the West Village. Owner Kerrilynn Pamer’s decision to switch boroughs was more about a better space than foot traffic. (When does that happen in NYC?)To back up her claim, she’s decked out her new shop to resemble an old-fashioned department store with beige carpeting, velvet drapes in the dressing rooms, and vintage displays from Bergdorf Goodman.The elegant design works as the perfect backdrop for stock from designers like Nieves Lavi, Mint, 3.1 by Phillip Lim, See by Chloé, Rodebjer, and Sonia Rykiel. In the mix with Goldenbleu and Dolce Vita shoes, Alek Wek handbags, and Twinkle jewelry are sweatshirts, bangles, and clutches made exclusively for her in-house label.So it looks like even on this side of the East River, things are going swimmingly.Castor & Pollux, 238 West 10th Street, between Hudson and Bleecker Streets (212-645-6572 or castorandpolluxstore.com).