The origin stories for each matrilineage describe how different groups arrived in the Trobriands from under the ground or by canoe and claimed garden and hamlet lands as their own. These claims were often contested by others who arrived later, so that subdivisions of matrilineages occurred. American whalers were in the northern Massim during the 1840s, and twenty years later Queensland's blackbirding ships made frequent kidnapping excursions to other islands in the vicinity. In the 1890s, Germans periodically sailed from New Britain to purchase tons of Trobriand yams, while wood carvings, decorated shells, and canoe prows were already becoming part of museum collections. The turn of the century marked the establishment of the Methodist Overseas Mission (now the United Church Mission) on Kiriwina, followed in 1905 by the arrival of Dr. Rayner Bellamy, the first Australian resident government officer. Bellamy spent ten years in charge of the government station on Kiriwina and assisted C. G. Seligman with ethnographic information during Seligman's Massim research. Following his mentor, Bronislaw Malinowski stopped on Kiriwina and then stayed for two years between 1915 and 1918. The Sacred Heart Catholic Mission arrived in the 1930s but during World War II all resident Europeans were evacuated. Australian and U.S. troops set up a hospital and two airstrips on Kiriwina. Although no battles were fought the area served as a staging ground for planes en route to Rabaul and the Coral Sea. In 1950, when Harry Powell arrived to undertake ethnographic research, surprisingly few fundamental cultural changes had occurred. Even in 1990, kula, the interisland exchange of arm shells and necklaces, was as intense as ever, while yam harvests and women's mortuary distributions remain as politically dynamic.