Apple Inc missed Wall Streets lofty target for iPhone sales over the crucial holiday shopping season and offered a weaker-than-expected forecast for this quarter, sending its shares down 8 percent on Monday. The worlds most valuable technology company sold a record 51 million iPhones in the quarter, but that was shy of the 55 million or so analysts had expected, reflecting intense competition from arch-foe Samsung Electronics during the crucial period. The company forecast sales of $42 billion to $44 billion this quarter, which investors anticipate will be brisker than usual because of its recently sealed deal to sell iPhones through China Mobile Ltd, the countrys No. 1 carrier. Wall Street was expecting $46 billion, on average.