John Lennon never really made a terrible solo record. Even Paul McCartney had his "Live and Let Die." But great songwriting teams don't split via mitosis-you rarely get two parts equal to the original whole.

Such is the case with Polvo, the now-defunct Chapel Hill outfit conceived in a UNC Spanish class by guitarist/vocalist Ash Bowie and David Brylawski. Of the early-90s local acts to receive national attention, Polvo were perhaps the most daring, combining Brylawski's love of Eastern instrumentation and Bowie's blurry pawn-shop guitars and sociopathic pop sensibilities. The effect was noisy, dizzy and arresting, a cosmic caterwaul that somehow rocked like Sabbath infused with the arty intellect of Sonic Youth.

Yesterday and Tomorrow's Shells shows Ash (under the name Libraness) cleaning his closet. Comprised of lo-fi 4-track recordings scraped together during his concurrent stints in Polvo and Helium (where he served as bassist), these tracks sound only slightly reworked from their scratchy originals. The acoustic guitar on "No Separation" sounds plucked and harsh, as incompletely realized as the song itself. "You Are My Foreign Film" could well be an early Polvo sketch, with Bowie's spectral vocals bleeding over an eastern guitar lead.

It's a bit of a flip to see Bowie use sounds that were mostly Brylawski's forte. It's also interesting that most of the sitar-like effects on Yesterday and Tomorrow's Shells were stitched together with little more than a piano and a series of effects pedals.

Intriguing as they are, though, few of these songs qualify as more than engaging demo fodder. "Toy Planetarium" could become a palatial epic of horns, bells and keyboards, but its lax structure lets it fizzle.

Much like Polvo's final two-night stand in Chapel Hill two years ago, this record is loaded with savvy introductions and good songwriting. But like the band's final show, where broken guitar strings and a malfunctioning microphone sidelined them for the first ten minutes, it comes up a little short on poise.

As for the other half of the old songwriting team, David Brylawski showed up at this year's Transmissions Festival at the Cat's Cradle with his new band Idle Swords, a mellow acoustic outfit that sounds neither like Polvo nor Eastern.

So much for mitosis.