Motorola announced its quarterly results for the September quarter, and we found one line item of particular interest: The company said it shipped 100,000 Xoom Android tablets during the quarter, a number that falls short of the number of iPads that Apple sells in a single day.

During the same quarter, Apple shipped some 11.12 million iPads, which is approximately 121,000 per day over the course of the 92 day quarter. Making the comparison even rougher on the one-time “iPad-killer” Xoom, is the fact that Apple’s numbers represent iPad sold, while Moto’s numbers are merely the number of tablets shipped, not the number of tablets sold.

To offer some context for those numbers, we offer the following chart.

When the Xoom was first released in March, it was heralded as an iPad-killer, the device that was going to do to the tablet market what hordes of Android smartphones had done to the iPhone in the smartphone market. It turned out, however, that no one actually wanted the iPad-killing device and instead opted for iPads.

So far, that’s been the case with every other Android tablet, at least until Amazon came along with the Kindle Fire, a 7” device the company is selling at a loss. As this author theorized in May, Amazon’s ecosystem of content and infrastructure offers an experience that makes the company’s tablet desirable to consumers.

Amazon managed to pre-sell 250,000 Kindle Fires in a little more than a week, which in and of itself is more than two and a half times Moto’s quarterly Xoom sales.

In the meanwhile, Motorola Mobility turned in a solid quarter despite the sad Xoom shipment numbers. The company grew revenue from US$2.4 billion in Q3 of 2010 to $3.3 billion, and increased Android smartphone sales to 4.8 million units, up one million units year-over-year.

Total mobile handset sales for the quarter were 11.6 million units, up from 9.1 million units in Q3 of 2010. That means the company grew sales of features phones as well as smartphones.

Google is in the process of buying Motorola Mobility, and the company didn’t host a conference call with analysts.

Thanks to PC Magazine for catching this factoid in Moto’s earning report.