http://www.onwar.com/chrono/1942/sep42/f18sep42.htm
American reinforce Guadalcanal
Friday, September 18, 1942 www.onwar.com
US Marine reinforcements arrive on Guadalcanal [photo at link]
In the Solomon Islands... On Guadalcanal, six transports arrive bringing supplies and the US 7th Marine Regiment. The American base now has 23,000 men and adequate supplies.
In New Guinea... Japanese General Horii, in response to orders and supply difficulties begins to pull back some of his forces around Buna and Gona.
On Madagascar... The British land troops on the east coast of the French governed island at Tamatave.